Parameterise ColumnIndexer

[mrmr1993]

This PR builds upon #2948, adding a type parameter to ColumnIndexer corresponding to the parameter for Column. This retains the usize type everywhere for now.

[codecov]

Codecov Report

Attention: Patch coverage is 86.36364% with 3 lines in your changes missing coverage. Please review.

Project coverage is 76.61%. Comparing base (21c8196) to head (f3b8e20).
Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
msm/src/ffa/mod.rs	0.00%	2 Missing ⚠️
msm/src/circuit_design/capabilities.rs	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2949      +/-   ##
==========================================
- Coverage   76.61%   76.61%   -0.01%     
==========================================
  Files         255      255              
  Lines       60855    60867      +12     
==========================================
+ Hits        46626    46633       +7     
- Misses      14229    14234       +5     

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