feat: Add method to calculate historical standings for any week

[DesiPilla]

This PR is to replace another attempt.

The tiebreaking process is quite complicated, but this follows all tiebreaking levels, subject to a league's specific tiebreaker rules.

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (62700b2) 80.60% compared to head (73bab47) 81.03%.

Files	Patch %	Lines
espn_api/football/helper.py	91.89%	6 Missing ⚠️
espn_api/football/league.py	87.50%	3 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #515      +/-   ##
==========================================
+ Coverage   80.60%   81.03%   +0.42%     
==========================================
  Files          59       60       +1     
  Lines        2114     2209      +95     
==========================================
+ Hits         1704     1790      +86     
- Misses        410      419       +9     

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[DesiPilla]

@cwendt94 looks like we don't have any test leagues that use H2H_RECORD as the tiebreaker, but otherwise this PR is set.

[cwendt94]

@DesiPilla could you move all of the helper functions in its own file helper.py so that we don't bloat the league object.

[DesiPilla]

@cwendt94 I agree that's the cleaner way to do it. I moved everything over now. I'm making some test cases for the sorting criteria that don't get run by default so that we have better code coverage.

[cwendt94]

Thank you, this is looking good!

[DesiPilla]

@cwendt94 alright the coverage should be good now.

[cwendt94]

@DesiPilla great work and thanks for adding the coverage!