pkg_resources is deprecated and we started pinning back setuptools to avoid problems here in #9657. We should stop using pkg_resources and unpin setuptools.

I took a crack at fixing this for the josepy repo at certbot/josepy#158. I suspect a similar approach could be taken here, however, there's significantly more work to be done and importlib_metadata will need to be used to deal with plugins. After further scoping out the work here, I think there's a good chance this should probably be done over multiple PRs. Perhaps one PR could focus on testing and another could focus on plugins.

I'm also throwing this in the current milestone for visibility for now at least.