feat(cloud-assembly-schema): add feature flag report as a possible artifact

[rix0rrr]

This gives libraries the opportunity to report the feature flags they support, and what values they saw during synthesis.

I purposely did not bump the schema version, since I want this feature to be fully incremental without disturbing existing users: there is no consumption of this new schema yet, that will come later, but we don't want to force people to upgrade their CLI's unnecessarily. That's bad DX.

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.01%. Comparing base (9545430) to head (0ee6e87).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #590   +/-   ##
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  Coverage   79.01%   79.01%           
=======================================
  Files          46       46           
  Lines        7085     7085           
  Branches      790      791    +1     
=======================================
  Hits         5598     5598           
  Misses       1468     1468           
  Partials       19       19           

Flag	Coverage Δ
suite.unit	79.01% <ø> (ø)

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