Refactor quality reports

[zhiltsov-max]

Motivation and context

An extract from #8953

• Symbols in quality report computation are made public
• Added some type annotations
• Updated quality computation rq job status handling to include the scheduled status as well

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have created a changelog fragment
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 48.48485% with 51 lines in your changes missing coverage. Please review.

Project coverage is 73.41%. Comparing base (9892390) to head (bf5d53d).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9026      +/-   ##
===========================================
+ Coverage    73.40%   73.41%   +0.01%     
===========================================
  Files          418      418              
  Lines        44340    44345       +5     
  Branches      3870     3870              
===========================================
+ Hits         32548    32557       +9     
+ Misses       11792    11788       -4     

Components	Coverage Δ
cvat-ui	77.38% <ø> (+<0.01%)	⬆️
cvat-server	70.13% <48.48%> (+0.01%)	⬆️

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud