[BUGFIX] Generate database documentation via typo3 command

[thomaslow]

Fixes #1437

This pull request moves the Build/Documentation/dbdocs code to the Classes/Command/DbDocs directory and uses a typo3 command (instead of a composer script) to trigger the generation of the rst file Documentation/Developers/Database.rst.

Todo

• generated rst file does not include general table description

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (da70a47) to head (733aa4b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #1486   +/-   ##
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