add sql source and reader

[Oisin-M]

Description

Opening for visibility. Related to #809.

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.18%. Comparing base (fc7f702) to head (17bd321).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #810   +/-   ##
========================================
  Coverage    85.18%   85.18%           
========================================
  Files          177      177           
  Lines        13711    13711           
  Branches       680      680           
========================================
  Hits         11680    11680           
  Misses        1840     1840           
  Partials       191      191           

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