Make event-related identifiers in cvat-core consistent

[SpecLad]

Motivation and context

These identifiers are inconsistent with the server-side code, and sometimes with each other (what's a logger and what's a log?), and it's breaking my brain.

Rename everything as follows:

1. Event: the thing being logged.
2. Logger: the thing doing the logging.
3. Scope: the type of an event.

How has this been tested?

Manual testing.

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)
• [ ] I have increased versions of npm packages if it is necessary
  (cvat-canvas,
  cvat-core,
  cvat-data and
  cvat-ui)

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]

Codecov Report

Merging #7482 (022308b) into develop (6260232) will increase coverage by 0.01%.
The diff coverage is 98.71%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #7482      +/-   ##
===========================================
+ Coverage    83.53%   83.54%   +0.01%     
===========================================
  Files          373      373              
  Lines        39693    39693              
  Branches      3718     3718              
===========================================
+ Hits         33157    33163       +6     
+ Misses        6536     6530       -6     

Components	Coverage Δ
cvat-ui	79.43% <98.71%> (+0.02%)	⬆️
cvat-server	87.32% <ø> (+<0.01%)	⬆️