feat: Add engineering-standards

[RasmusRendal]

This project is severely missing a Nix dev shell, and engineering-standards
just became a very easy way to do it.

[emgrav]

Wait, actually, quick question: The omnibus CI workflow is not running due to an input error, and it seems to mistakenly not be marked as a required job. I think we can not merge this until the CI actually passes, and I would anticipate problems with at least the REUSE compliance job from this PR.

stale

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.18%. Comparing base (ec0ec43) to head (eac2573).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #30   +/-   ##
=======================================
  Coverage   74.18%   74.18%           
=======================================
  Files           5        5           
  Lines         275      275           
=======================================
  Hits          204      204           
  Misses         71       71           

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