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 85.34%. Comparing base (e2c2fe7) to head (d617132).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #810   +/-   ##
========================================
  Coverage    85.34%   85.34%           
========================================
  Files          184      184           
  Lines        14565    14565           
  Branches       723      723           
========================================
  Hits         12431    12431           
  Misses        1923     1923           
  Partials       211      211           

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