Refactor/unify/extract shutil.rmtree callbacks (and avoid repetition)

[abravalheri]

Summary of changes

I noticed that there are at least 2 implementations of shutil.rmtree callbacks in setuptools: one for easy_install and one for bdist_wheel. There is also other places in setuptools that we don't have those callbacks (so potentially still subject to errors on Windows?).

So this PR tries to unify these 2 separated implementations.
I have chosen to extract the implementation from easy_install.
One notable difference though is that bdist_wheel's implementation always try to apply the chmod callback when it fails, while the easy_install implementation is more conservative and only applies the callback on Windows (similar to the suggestion in https://github.com/python/cpython/issues/87823#issuecomment-1093908280)... So that might generate a bit of change in behaviour, but with a bit of luck should be compatible.

The name _shutil was used for the lack of a better name/imagination, and can be changed.

Closes

Pull Request Checklist

• Changes have tests
• News fragment added in newsfragments/.
  (See documentation for details)

[abravalheri]

According to the comments, it seems that the specific error that the chmod workaround is able to fix is only possible on Windows.

That is why some parts of the old code restrict the chmod workaround the to only Windows platforms.

This PR keeps the workaround homogeneously Windows-specific for all usages. If we have any reported failure we can relax the conditions a bit in a future PR.