ENH: Option to return -inf/inf as lower/upper bound of quantiles, see…
Add `bounded` keyword arg to `quantile` and `qcut` functions to enable unbounded quantiles with lower/upper bounds of -inf/inf.

- [x] closes #17282
- [ ] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Hello @dberenbaum! Thanks for submitting the PR.



 - In the file [`pandas/core/reshape/tile.py`](https://github.com/pandas-dev/pandas/blob/48b5f5c6298ff30a9184f1ae21096d5a017dbfb1/pandas/core/reshape/tile.py), following are the PEP8 issues :

> [Line 241:70](https://github.com/pandas-dev/pandas/blob/48b5f5c6298ff30a9184f1ae21096d5a017dbfb1/pandas/core/reshape/tile.py#L241): [W291](https://duckduckgo.com/?q=pep8%20W291) trailing whitespace

 Closing for now to rework this PR.