HotfixStatusChecker: improvements

[Tom-Willemsen]

• Use gitpython instead of executing things like cd ... && git ... using a shell and parsing the result.
• Use the normal python logging infrastructure instead of print("DEBUG: ...")
• Migrate to a standard pyproject.toml setup

[FreddieAkeroyd]

Also I had to hardcode ignoring tools\cygwin\master changes for the moment as we patched it and the are a lot of them. Ignore list should probably be a jenkins parameter, or ideally we'd patch in a way that they didn't show up e.g. add the commit locally or add it to common upstream so it is expected