Vectorized grouping by multiple column

[akuzm]

Paste the values together and use the umash hash of the resulting value for grouping, like we do for the text keys.

Up to 150% improvement on some tsbench queries.

[codecov]

Codecov Report

Attention: Patch coverage is 89.44954% with 23 lines in your changes missing coverage. Please review.

Project coverage is 81.90%. Comparing base (59f50f2) to head (80008b0).
Report is 797 commits behind head on main.

Files with missing lines	Patch %	Lines
...odes/vector_agg/hashing/hash_strategy_serialized.c	88.70%	2 Missing and 19 partials ⚠️
tsl/src/nodes/vector_agg/grouping_policy_hash.c	90.90%	0 Missing and 1 partial ⚠️
...rc/nodes/vector_agg/hashing/batch_hashing_params.h	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7754      +/-   ##
==========================================
+ Coverage   80.06%   81.90%   +1.83%     
==========================================
  Files         190      248      +58     
  Lines       37181    45622    +8441     
  Branches     9450    11404    +1954     
==========================================
+ Hits        29770    37366    +7596     
- Misses       2997     3767     +770     
- Partials     4414     4489      +75     

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