Add C++ CQM::remove_constraints_if() method

[arcondello]

This method provides a significant speedup when removing constraints in bulk at the C++ level.

[codecov[bot]]

Codecov Report

Merging #1344 (cb29a11) into main (37d6a6c) will increase coverage by 0.01%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1344      +/-   ##
==========================================
+ Coverage   94.92%   94.94%   +0.01%     
==========================================
  Files          95       95              
  Lines        9720     9754      +34     
==========================================
+ Hits         9227     9261      +34     
  Misses        493      493              

Impacted Files	Coverage Δ
dimod/include/dimod/constrained_quadratic_model.h	90.90% <100.00%> (+0.22%)	:arrow_up:
...estscpp/tests/test_constrained_quadratic_model.cpp	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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