feat: add patreon_url in settings model

[snitin315]

Refers 3rd point in fossasia/open-event-frontend#4960

Please also add https://www.patreon.com as an option

[codecov]

Codecov Report

Merging #7243 into development will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           development    #7243   +/-   ##
============================================
  Coverage        63.02%   63.03%           
============================================
  Files              259      259           
  Lines            13034    13036    +2     
============================================
+ Hits              8215     8217    +2     
  Misses            4819     4819           

Impacted Files	Coverage Δ
app/api/schema/settings.py	100.00% <100.00%> (ø)
app/models/setting.py	94.01% <100.00%> (+0.05%)	⬆️

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