feat: add briefs and generate autobriefs

[rich-iannone]

This adds functionality for adding brief pieces of text for a validation step, and it also auto-generates autobriefs, which hold single-sentence expectation statements (one per step). On top of this, the lang= and locale= args have been added to the Validate class. This allows the autobriefs to be translated to the lang value (languages are: "en", "fr", "de", "it", "es", "pt", "tr", "zh", "ru", "pl", "da", "sv", and "nl").

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 98.54015% with 2 lines in your changes missing coverage. Please review.

Project coverage is 99.15%. Comparing base (c5430a4) to head (b6b5786).

Files with missing lines	Patch %	Lines
pointblank/validate.py	98.50%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #71      +/-   ##
==========================================
- Coverage   99.18%   99.15%   -0.04%     
==========================================
  Files          14       15       +1     
  Lines        3057     3184     +127     
==========================================
+ Hits         3032     3157     +125     
- Misses         25       27       +2     

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