BUG: Change numeric_only default to True
I know I have to correct the other tests that fail due to this change. But I want confirmation that this PR is headed in the right direction before doing so.

- [X] closes #7308
- [X] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [X] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [X] Added an entry in the latest `doc/source/whatsnew/v1.5.0.rst` file if fixing a bug or adding a new feature.



Hello @phofl, do you think this would be the way to go?

I am still having some errors in the tests, when I run

```bash
pytest -v pandas/tests/frame/methods/test_quantile.py
...
======== 73 passed, 8 xfailed, 6 warnings in 2.46s =========
```
Getting al the warnings produced by my modifcation, even though I included the next line as decorator to those tests
`python
@pytest.mark.filterwarnings("ignore:In future versions of pandas, numeric_only")
`
Full output below

<details>

=================== test session starts ====================
platform linux -- Python 3.8.12, pytest-6.2.5, py-1.11.0, pluggy-1.0.0 -- /home/pi/anaconda3/envs/pandas-dev/bin/python
cachedir: .pytest_cache
hypothesis profile 'ci' -> deadline=None, suppress_health_check=[HealthCheck.too_slow], database=DirectoryBasedExampleDatabase('/home/pi/git/mypandas/.hypothesis/examples')
rootdir: /home/pi/git/mypandas, configfile: pyproject.toml
plugins: asyncio-0.17.2, cython-0.1.1.post0, cov-3.0.0, hypothesis-6.36.0, instafail-0.4.1, forked-1.4.0, xdist-2.5.0
asyncio: mode=legacy
collected 81 items                                         

pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_numeric_only_default_false_warning PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_sparse[df0-expected0] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_sparse[df1-expected1] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_date_range PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_axis_mixed PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_axis_parameter PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_interpolation PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_interpolation_datetime PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_interpolation_int PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_multi PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_datetime PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[datetime64[ns]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[datetime64[ns, US/Pacific]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[timedelta64[ns]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[Period[D]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_invalid PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_box PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_nan PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_nat PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_empty_no_rows_floats PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_empty_no_rows_ints PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_empty_no_rows_dt64 PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_empty_no_columns PASSED
pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_item_cache PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[interval[int64, right]-DataFrame] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[interval[int64, right]-Series] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[period[D]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[period[D]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[datetime64[ns, US/Pacific]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[datetime64[ns, US/Pacific]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[timedelta64[ns]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[timedelta64[ns]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[Int64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[Int64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[Float64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea[Float64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[interval[int64, right]-DataFrame] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[interval[int64, right]-Series] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[period[D]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[period[D]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[datetime64[ns, US/Pacific]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[datetime64[ns, US/Pacific]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[timedelta64[ns]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[timedelta64[ns]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[Int64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[Int64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[Float64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_with_na[Float64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[interval[int64, right]-DataFrame] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[interval[int64, right]-Series] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[period[D]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[period[D]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[datetime64[ns, US/Pacific]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[datetime64[ns, US/Pacific]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[timedelta64[ns]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[timedelta64[ns]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[Int64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[Int64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[Float64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_all_na[Float64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[interval[int64, right]-DataFrame] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[interval[int64, right]-Series] XFAIL
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[period[D]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[period[D]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[datetime64[ns, US/Pacific]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[datetime64[ns, US/Pacific]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[timedelta64[ns]-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[timedelta64[ns]-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[Int64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[Int64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[Float64-DataFrame] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_quantile_ea_scalar[Float64-Series] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_numeric[float64-expected_data0-expected_index0-1] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_numeric[int64-expected_data1-expected_index1-1] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_numeric[float64-expected_data2-expected_index2-0] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_numeric[int64-expected_data3-expected_index3-0] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_datelike[datetime64[ns]-expected_data0-expected_index0-1-datetime64[ns]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_empty_datelike[datetime64[ns]-expected_data1-expected_index1-0-datetime64[ns]] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_datelike_numeric_only[expected_data0-expected_index0-1] PASSED
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_datelike_numeric_only[expected_data1-expected_index1-0] PASSED

===================== warnings summary =====================
../../anaconda3/envs/pandas-dev/lib/python3.8/site-packages/pytest_asyncio/plugin.py:191
  /home/pi/anaconda3/envs/pandas-dev/lib/python3.8/site-packages/pytest_asyncio/plugin.py:191: DeprecationWarning: The 'asyncio_mode' default value will change to 'strict' in future, please explicitly use 'asyncio_mode=strict' or 'asyncio_mode=auto' in pytest configuration file.
    config.issue_config_time_warning(LEGACY_MODE, stacklevel=2)

pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_axis_mixed
  /home/pi/git/mypandas/pandas/tests/frame/methods/test_quantile.py:124: FutureWarning: In future versions of pandas, numeric_only will be set to False by default, and the datetime/timedelta columns will be considered in the results. To not consider these columnsspecify numeric_only=True and ignore this warning.
    result = df.quantile(0.5, axis=1)

pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_datelike_numeric_only[expected_data0-expected_index0-1]
pandas/tests/frame/methods/test_quantile.py::TestQuantileExtensionDtype::test_datelike_numeric_only[expected_data1-expected_index1-0]
  /home/pi/git/mypandas/pandas/tests/frame/methods/test_quantile.py:786: FutureWarning: In future versions of pandas, numeric_only will be set to False by default, and the datetime/timedelta columns will be considered in the results. To not consider these columnsspecify numeric_only=True and ignore this warning.
    result = df[["a", "c"]].quantile(0.5, axis=axis)

../../anaconda3/envs/pandas-dev/lib/python3.8/site-packages/_pytest/cacheprovider.py:428
  /home/pi/anaconda3/envs/pandas-dev/lib/python3.8/site-packages/_pytest/cacheprovider.py:428: PytestCacheWarning: cache could not write path /home/pi/git/mypandas/.pytest_cache/v/cache/nodeids
    config.cache.set("cache/nodeids", sorted(self.cached_nodeids))

../../anaconda3/envs/pandas-dev/lib/python3.8/site-packages/_pytest/stepwise.py:49
  /home/pi/anaconda3/envs/pandas-dev/lib/python3.8/site-packages/_pytest/stepwise.py:49: PytestCacheWarning: cache could not write path /home/pi/git/mypandas/.pytest_cache/v/cache/stepwise
    session.config.cache.set(STEPWISE_CACHE_DIR, [])

-- Docs: https://docs.pytest.org/en/stable/warnings.html
- generated xml file: /home/pi/git/mypandas/test-data.xml --
=================== slowest 30 durations ===================
0.07s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_numeric_only_default_false_warning
0.02s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_datetime
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_box
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_nan
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[Period[D]]
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_empty_no_rows_dt64
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_dt64_empty[datetime64[ns]]
0.01s call     pandas/tests/frame/methods/test_quantile.py::TestDataFrameQuantile::test_quantile_nat

(21 durations < 0.005s hidden.  Use -vv to show these durations.)
======== 73 passed, 8 xfailed, 6 warnings in 2.46s =========

</details>


 also pls rebase Should we modify EXAMPLES in documentation? 
https://github.com/pandas-dev/pandas/blob/0ccad3840958cc7fff5aa358a08e33acca13dd00/pandas/core/frame.py#L10573-L10580 @NumberPiOso can you merge master and ping on green thanks @NumberPiOso 