Modify backend entrypoint to wait redis (inmem and ondisk)

[azhavoro]

Currently CVAT is just waiting for the database to start the server process and the worker processes, but if redis instances (for queue and cache processing) are not running we will get a non-functional cvat. This PR adds availability checking for redis_ondisk and redis_inmem

Motivation and context

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)
• 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 #7479 (2ca4502) into develop (e8384f8) will decrease coverage by 0.01%.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #7479      +/-   ##
===========================================
- Coverage    83.55%   83.54%   -0.01%     
===========================================
  Files          375      375              
  Lines        39752    39752              
  Branches      3734     3734              
===========================================
- Hits         33213    33210       -3     
- Misses        6539     6542       +3     

Components	Coverage Δ
cvat-ui	79.44% <ø> (-0.03%)	⬇️
cvat-server	87.32% <ø> (+<0.01%)	⬆️

[SpecLad]

We already have a script to wait for these, wait_for_deps.sh. I would suggest to call this script in the command for fcgi-program:uvicorn in server.conf. That way, the server will check the dependencies again if the process is restarted.