bugfix: stopit import causes exception

[reevesc7]

What does this PR do?

This PR fixes importing stopit by adding a fake pkg_resources module with a get_distribution() function.

Where should the reviewer start?

tpot.utils.eval_utils.py is the only changed file.

How should this PR be tested?

The PR passed local tests and CI tests.

Any background context you want to provide?

This PR serves as an alternative to #1391, and only one of the two should be merged.

stopit is the only TPOT dependency which depends on pkg_resources.
pkg_resources has been removed from setuptools, so importing stopit raises and exception.

This PR creates a faux pkg_resources module which contains a get_distribution() function (the only call stopit makes).
Under the hood, the faux module uses the modern dynamic package versioning solution importlib.metadata.version().

Because my branch was originally created from EpistatisLab:main, this PR also merges those commits into EpistasisLab:dev.

What are the relevant issues?

#1391 is an alternative solution, which removes stopit dependency entirely.

Questions:

• Do the docs need to be updated? No
• Does this PR add new (Python) dependencies? No