Make TurnKey custom package repos "best practice"

[JedMeister]

We've make a lot of progress towards improving our custom software for the v19.x release. But there is still more to do to bring the overall quality up to scratch - and make them all consistent. We aren't pushing our packages into Debian so they don't need to be perfect but it would be good to at least get close to "Debian best practice" for all of our custom software.

There are a few packages which are close and could be used as "reference" of how they should be:

• https://github.com/turnkeylinux/fab

  • see Release ready fab#47

• https://github.com/turnkeylinux/turnkey-version

  • see Bugfix, minor functional/internal changes, linting, formatting & packaging updates and GitHub action to run PR lint/typing tests turnkey-version#10

• https://github.com/turnkeylinux/tkl-installer (mostly pretty good right from the start)

Particularly noteworthy TODOs:

• Updating files in debian/ to be compliant with their stated "Standards-Version" (currently v4.7.2 - but not all are actually compliant...). Specific files that need attention are rules (most should be pretty good already), control and copyright.
• Running linitian on all of our packages (tkl-installer is the only one that is close to passing).
• Run linting and type checking on all packages (github actions - initial implementation of ruff & mypy in turnkey-version PR noted above). Include linitian as well
• Proper release notes (changelog) for each release - see the fab PR noted above in particular. Might be good to consider actually including a "proper" changelog? (would need consideration for exactly how we do that - including how we adjust autoversion to still work for "in progress" changes "in between" releases.
• plus more no doubt...