Change `Unsupported` doc tag to `Best effort`

[TotoGaz]

Also add a minimal example on how to configure sccache in the Dockerfile

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 53.21%. Comparing base (d85399d) to head (02beeb0).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #3102 +/- ## ======================================== Coverage 53.21% 53.21% ======================================== Files 989 989 Lines 83602 83602 ======================================== Hits 44492 44492 Misses 39110 39110 ```

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