DEV/MNT: migrate to GitHub Actions and pyproject.toml [LCLSPC-603]

[klauer]

Description

• Upgrading by way of https://github.com/pcdshub/pcds-python-migration-tools
• hutch-python no longer uses Travis CI and has migrated to GitHub Actions for continuous integration, testing, and documentation deployment.
• hutch-python has been migrated to use setuptools-scm, replacing versioneer, as its version-string management tool of choice.
• hutch-python has been migrated to use the modern pyproject.toml, replacing setup.py and related files.
• Older language features and syntax found in the repository have been updated to Python 3.9+ standards by way of pyupgrade.
• Sphinx 6.0 is now supported for documentation building. docs-versions-menu replaces doctr-versions-menu and doctr usage for documentation deployment on GitHub Actions. The deployment key is now no longer required.
• pyupgrade was used to update annotations.
• pycln was used to clean up imports

Motivation and Context

• Migrating because we want to migrate our projects from Travis CI for one

How Has This Been Tested?

• GitHub Actions

Where Has This Been Documented?

This PR and Jira LCLSPC-603

[klauer]

One test consistently failing: FAILED hutch_python/tests/test_tstpython.py::test_tstpython_ipython Need to look into details...

Some other weird output in the log, but discussed in side channels it's probably intentional-ish

[tangkong]

This might be the same test that's been failing? https://github.com/pcdshub/hutch-python/issues/354 (yep https://app.travis-ci.com/github/pcdshub/hutch-python/jobs/588574480#L1011)

This also probably closes #335 ?

[klauer]

(Merging and bypassing branch restrictions; reviewers indicated that IPython-related bug should be solved in a separate PR)