Rails 7 Upgrade

[BenjaminSchaaf]

I've upgraded citadel to Rails 7.1, allowing it to run on supported ruby 3.1. This kills most of the pain-points setting up a development environment and deploying citadel.

[codecov]

Codecov Report

Attention: Patch coverage is 95.52239% with 3 lines in your changes missing coverage. Please review.

Project coverage is 95.21%. Comparing base (3b88d51) to head (cfe100d).
Report is 10 commits behind head on master.

Files	Patch %	Lines
app/models/league.rb	66.66%	1 Missing ⚠️
app/services/leagues/matches/generation_service.rb	0.00%	1 Missing ⚠️
...ces/leagues/matches/pick_bans/deferring_service.rb	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #552      +/-   ##
==========================================
+ Coverage   95.16%   95.21%   +0.04%     
==========================================
  Files         193      193              
  Lines        4533     4532       -1     
==========================================
+ Hits         4314     4315       +1     
+ Misses        219      217       -2     

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[BenjaminSchaaf]

Since there's been no objections to this I'll be merging it.