Modernize ClubCpG dependencies and dev environment

[canthonyscott]

This pull request includes the following:

• A major overhaul and modernization of the ClubCpG dependencies.
• setup.py removed in favor of a pyproject.toml
• All project dependencies updated to modern versions
• Support of python 3.5, 3.6, 3.7, and 3.8 dropped as these versions are End of Life or near so
• Minimum version of python is now 3.9
• Added GitHub Actions workflows to automate testing of python 3.9 and 3.10
• Updated readthedocs build configuration ahead of deprecation of old method
• Added a workflow to automatically build and publish new versions of the package to PyPi when new tags are created
• Additions of some new error handling when working on small datasets
• Removal of one unit test that was dependent on pre-trained PReLIM models on an ancient version of scikit-learn

No logic has been changed with ClubCpG itself.

A Minor version bump from v.0.2.x to v0.3.0 has been included mostly to indicate that these updates will no longer work with older versions of Python

[canthonyscott]

@cjgunase I added you as a reviewer so you could put your eyes on this before I merge it to master and deploy