Move common code to assemblies

[JeremyKuhne]

Most of what was in the Common folder was only used in one place or could live in a shared assembly. Moved what I easily could.

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.74723%. Comparing base (f0e509c) to head (3644d14).
Report is 5 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12506         +/-   ##
===================================================
+ Coverage   75.69129%   75.74723%   +0.05594%     
===================================================
  Files           3151        3156          +5     
  Lines         635805      636084        +279     
  Branches       46978       47001         +23     
===================================================
+ Hits          481249      481816        +567     
+ Misses        151124      150808        -316     
- Partials        3432        3460         +28     

Flag	Coverage Δ
Debug	75.74723% <100.00000%> (+0.05594%)	⬆️
integration	18.20021% <100.00000%> (+0.01976%)	⬆️
production	49.32190% <100.00000%> (+0.10251%)	⬆️
test	97.04658% <ø> (+0.00149%)	⬆️
unit	46.49502% <0.00000%> (+0.23706%)	⬆️

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