Support BYPOLYGON option for GEOSEARCH

[KarthikSubbarao]

This is a draft PR while I examine correctness of the BYPOLYGON search described here: #1755

It is functional, however the parts remaining are validation of correctness, adding .tcl testing, and optimizing.

Keeping this in a draft state until the GitHub issue is reviewed in more detail (and agreed upon) and until the parts above are completed.

[codecov]

Codecov Report

Attention: Patch coverage is 25.80645% with 92 lines in your changes missing coverage. Please review.

Project coverage is 70.90%. Comparing base (f31cf18) to head (d3c8681).
Report is 1 commits behind head on unstable.

Files with missing lines	Patch %	Lines
src/geohash_helper.c	18.07%	68 Missing ⚠️
src/geo.c	41.46%	24 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1809      +/-   ##
============================================
- Coverage     71.04%   70.90%   -0.15%     
============================================
  Files           123      123              
  Lines         65651    65764     +113     
============================================
- Hits          46644    46632      -12     
- Misses        19007    19132     +125     

Files with missing lines	Coverage Δ
src/geo.c	89.11% <41.46%> (-4.47%)	⬇️
src/geohash_helper.c	64.97% <18.07%> (-34.19%)	⬇️

... and 13 files with indirect coverage changes