Fixes remaining sqlalchemy orms

[havok2063]

This PR fixes the database connections for the remaining sqlalchemy orms and removes the AbstractConcreteBase, mainly for consistency with sdss5db.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.44%. Comparing base (a298b6e) to head (93461ed).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #309      +/-   ##
==========================================
- Coverage   88.44%   88.44%   -0.01%     
==========================================
  Files          42       42              
  Lines       24212    24201      -11     
  Branches      463      463              
==========================================
- Hits        21415    21404      -11     
  Misses       2765     2765              
  Partials       32       32              

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[albireox]

This looks good to me. I did a couple tests with opsdb and targetdb and it seems to work fine.