feat(cli): Add configuration file

[effigies]

Introduces a configuration file. The configuration file maps severities (ignore, warning, error) onto lists of partial issues. The partial issues are used to filter the issue list, and the severity of all matching issues are updated.

This is done in order of ignore, warning, error, so any issue that matches multiple will end with the highest severity.

Closes https://github.com/bids-standard/bids-validator/issues/1937.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.85%. Comparing base (06df2f8) to head (e6d3d93).
Report is 9 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2100      +/-   ##
==========================================
+ Coverage   85.69%   87.85%   +2.15%     
==========================================
  Files          91      133      +42     
  Lines        3782     6957    +3175     
  Branches     1220     1655     +435     
==========================================
+ Hits         3241     6112    +2871     
- Misses        455      750     +295     
- Partials       86       95       +9     

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