[python] Consolidate all _set_coords methods into single _util function

[nguyenv]

Issue and/or context:

As part of work for #3053.

Changes:

This is clean-up work.

This takes the separate implementations of _set_coords from _dataframe, _sparse_nd_array, _spatial_dataframe, and _soma_array into a single _util._set_coords. _cast_domainish was also moved out of SOMAArrayWrapper and into _util to support casting of domains and NEDs in _set_coord.

Note for reviewers:

I am unsure if _util.py is the appropriate place for this.

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 6 lines in your changes missing coverage. Please review.

Project coverage is 85.40%. Comparing base (a515eb7) to head (f464dfe).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3292      +/-   ##
==========================================
+ Coverage   84.62%   85.40%   +0.78%     
==========================================
  Files          52       52              
  Lines        5633     5517     -116     
==========================================
- Hits         4767     4712      -55     
+ Misses        866      805      -61     

Flag	Coverage Δ
python	85.40% <94.73%> (+0.78%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
python_api	85.40% <94.73%> (+0.78%)	⬆️
libtiledbsoma	∅ <ø> (∅)

[johnkerl]

This is beautiful ... thank you!!

[johnkerl]

I am unsure if _util.py is the appropriate place for this.

@nguyenv I think this is fine :)