Describe the default conf file locations in docs/Configuration.md

[starrify]

This is a minor doc change.

The list of default paths are taken from docs/DistributedQuickstart.md.

[Xuanwo]

Thanks a lot!

[codecov-commenter]

Codecov Report

Patch coverage has no change and project coverage change: -0.17 ⚠️

Comparison is base (2354d12) 29.63% compared to head (c71b40e) 29.46%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1706      +/-   ##
==========================================
- Coverage   29.63%   29.46%   -0.17%     
==========================================
  Files          49       49              
  Lines       17054    17056       +2     
  Branches     8214     8274      +60     
==========================================
- Hits         5054     5026      -28     
- Misses       6992     6996       +4     
- Partials     5008     5034      +26     

see 19 files with indirect coverage changes

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[sylvestre]

fyi, it was documented here:
https://github.com/mozilla/sccache/blob/main/docs/DistributedQuickstart.md
but it is better in this place indeed