Refactor settings TS functionality to use `@rails/request.js`

[pixeldesu]

Initial part of the refactor to use request.js instead of UJS, so we can switch to Turbo.

Testing:

• Check if removing anon blocks still works
• Check if adding and removing mute rules still works (disregarding #440)

[codecov[bot]]

Codecov Report

Merging #656 (c979a72) into main (fbabae9) will not change coverage. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #656   +/-   ##
=======================================
  Coverage   88.04%   88.04%           
=======================================
  Files         131      131           
  Lines        2284     2284           
=======================================
  Hits         2011     2011           
  Misses        273      273           

Impacted Files	Coverage Δ
app/controllers/ajax/mute_rule_controller.rb	65.90% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.