add BinaryApp app type

[gilesknap]

Adds a new type of app which downloads a standalone binary, checks its hash and places it in the entrypoints folder.

Also adds the argocd module to demo_configuration in order to demonstrate the feature.

[codecov]

Codecov Report

Attention: Patch coverage is 47.91667% with 25 lines in your changes missing coverage. Please review.

Project coverage is 44.48%. Comparing base (32ef01f) to head (0756498).

Files with missing lines	Patch %	Lines
src/deploy_tools/app_builder.py	16.66%	25 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #26      +/-   ##
==========================================
+ Coverage   42.55%   44.48%   +1.92%     
==========================================
  Files          23       24       +1     
  Lines         860      906      +46     
==========================================
+ Hits          366      403      +37     
- Misses        494      503       +9     

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[MJGaughran]

Module level constants are normally defined at the top of the file, just under the imports.