DateOffset add to ndarray
This is WIP to implement changes needed to allow DateOffset subclasses e.g. MonthEnd to be directly added to numpy.ndarray, e.g. `numpy.array(['2022-01-01'], dtype='datetime64') + pandas.offsets.MonthEnd(1)`

I need some guidance on:

- cython mechanism to check that passed ndarray is datetime64 dtype i.e.cython equivalent of pandas.api.types.is_datetime64_any_dtype
- how to approach adding unit tests? two ideas I have
  - somehow duplicate existing offset tests but run them on ndarray instead of Series?  looks on the surface to be more difficult to implement
  - apply a set of offsets to a predefined Series and ndarray equivalent, and then check results match

Many thanks!

- [x] closes #47014
- [ ] [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
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.
This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.