feat(col.bool): improve performance

[ernado]

name                     old time/op    new time/op    delta
ColBool_DecodeColumn-32    23.7µs ± 1%    23.2µs ± 2%     ~     (p=0.095 n=5+5)
ColBool_EncodeColumn-32    28.0µs ± 2%    21.9µs ± 2%  -21.72%  (p=0.008 n=5+5)

name                     old speed      new speed      delta
ColBool_DecodeColumn-32  2.11GB/s ± 1%  2.16GB/s ± 2%     ~     (p=0.095 n=5+5)
ColBool_EncodeColumn-32  1.79GB/s ± 2%  2.28GB/s ± 2%  +27.73%  (p=0.008 n=5+5)

kudos to @cristaloleg

[codecov]

Codecov Report

Merging #13 (787892f) into main (8706ec0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #13   +/-   ##
=======================================
  Coverage   79.56%   79.56%           
=======================================
  Files         105      105           
  Lines        4242     4242           
=======================================
  Hits         3375     3375           
  Misses        699      699           
  Partials      168      168           

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