Fix AtBMonthlyContractMarket payment multiplier

[Algebro7]

There was an error when calculating the payment multiplier using the CamOps unit rating method for AtBMonthly contracts, which was caused by incorrectly using the reputation score instead of the reputation modifier for determining this multiplier. This PR does a couple of things:

1. Fixes getReputationFactor() to use the camopsUnitRatingMod instead of the reputation score
2. Reverts the change in AtBMonthlyContractMarket and uses the AtBUnitRatingMod instead
3. Adds a getCamOpsUnitRatingMod() method to get the camops unit rating mod and support getReputationFactor()
4. Adds docstrings for everything

Closes #4952

[IllianiCBT]

Is there value in moving this into the Reputation class - cooking dinner so the class might be called something else? Call the new method something like getReputationModifier().

[Algebro7]

I did actually try to do that first, but there is already a different getReputationModifier() there that does something based on the unit experience levels instead. I wasn't sure how that was used and so I didn't want to mess with it--could you look at that when you get a minute and let me know what you think?

Thanks!

[IllianiCBT]

I’ll take a look once I’ve had dinner.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 10.45%. Comparing base (980d504) to head (b3341a5).
Report is 9 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #4954      +/-   ##
============================================
+ Coverage     10.44%   10.45%   +0.01%     
- Complexity     6005     6016      +11     
============================================
  Files           951      951              
  Lines        132875   132876       +1     
  Branches      19329    19329              
============================================
+ Hits          13876    13894      +18     
+ Misses       117648   117632      -16     
+ Partials       1351     1350       -1     

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[IllianiCBT]

LGTM

[Algebro7]

Thanks for the review, this should be fixed. I'm working on tests but that will likely take some more time/refactoring so I'll push those in a separate PR later.