Switch to Centralized Package Management (and also a minor Spectre.Console upgrade)

[waf]

• Switch to Centralized Package Management. Solutions and projects that are "test data" for our integration tests are excluded via a Directory.Packages.props inside the test data folder.
• Other minor updates:
  • Update Spectre Console dependency (minor update)
  • Sync Solution Items in slnx file.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.3%. Comparing base (84be0a1) to head (b4ab91f).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #502   +/-   ##
=====================================
  Coverage   80.3%   80.3%           
=====================================
  Files        126     126           
  Lines       9362    9362           
  Branches    1399    1399           
=====================================
  Hits        7519    7519           
  Misses      1355    1355           
  Partials     488     488           

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