tools/verifygitlog.py: Add git commit message checking.

[jimmo]

This adds verifygitlog.py from the main repo, adds it to GitHub workflows, and also pre-commit.

I spent a considerable amount of effort trying to make gitlint (https://jorisroovers.com/gitlint) work (for both the main repo and here) but it was not flexible enough to make it work with our rules. See https://github.com/jimmo/micropython/tree/gitlint-config

The three main limitations were:

• I ended up having to write a non-trivial amount of Python code as custom rules.
• It doesn't have a way to link to documentation or add suggestions like verifygitlog.py does.
• I couldn't find a way to make WIP and !fix commits work in pre-commit but not in CI.

So in the end it's just easier to keep using verifygitlog.py (even if it means duplicating it here).

This work was funded through GitHub Sponsors.

[dpgeorge]

Thanks!