Add entity groups to alternative and scenario filters

[soininen]

This PR implements entity group filtering in scenario and alternative filters.

Resolves spine-tools/Spine-Toolbox#3004

Checklist before merging

• Documentation (also in Toolbox repo) is up-to-date
• Release notes have been updated
• Unit tests have been added/updated accordingly
• Code has been formatted by black & isort
• Unit tests pass

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.42%. Comparing base (1245aca) to head (8ef4c8f).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #470      +/-   ##
==========================================
+ Coverage   80.38%   80.42%   +0.03%     
==========================================
  Files          77       77              
  Lines       10030    10049      +19     
  Branches     1477     1477              
==========================================
+ Hits         8063     8082      +19     
  Misses       1625     1625              
  Partials      342      342              

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