Bump min Ansible version to 2.16

[SirGitsalot]

Also:

• Modify GitHub workflows to run unit tests and lint using all supported Python versions (3.10, 3.11, and 3.12 as of now)
• Drop testing with Python 2.7 as it's no longer supported or required
• Run integration tests with Python 3.10
• Use the run-ansible-lint GitHub action rather than installing directly The action doesn't work when running outside of the root workspace directory.

This is one of multiple PRs to perform the upgrade; it fixes some issues but adds new issues (new linter errors due to a newer version of ansible-lint and broken role tests, to name a couple).