Fixed chunk and preview cache usage

[azhavoro]

Motivation and context

Usage of diskcache.Cache class leads to ignorig cache settings from base.py

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have added a description of my changes into CHANGELOG file
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (read 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.

[nmanovic]

LGTM

[Marishka17]

PR looks good to me, but I have several questions:

• Why is it needed to increase the default number of SHARDS?
• maybe need to make cache item keys more descriptive and the same?
  now it looks like this:

:1:djangohealtcheck_test
:1:1_0_Quality.COMPRESSED
:1:data_2_0_preview

:1:chunk_compressed_1_0
:1:local_preview_2_0
:1:cloud_preview_2_0

• Should we remove the previous cache (I mean data/cache/cache.db)?