Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `README.md`:
  Upstream updated copyright year, we don't mention it so kept our version.
- `app/controllers/admin/dashboard_controller.rb`:
  Not really a conflict, upstream change (removing the spam checker) too close
  to glitch-soc changes. Ported upstream changes.
- `app/models/form/admin_settings.rb`:
  Same.
- `app/services/remove_status_service.rb`:
  Same.
- `app/views/admin/settings/edit.html.haml`:
  Same.
- `config/settings.yml`:
  Same.
- `config/environments/production.rb`:
  Not a real conflict, upstream added a default HTTP header, but we have
  extra headers in glitch-soc.
  Added the header.

app/models/form/admin_settings.rb

@@ -35,7 +35,6 @@ class Form::AdminSettings
     mascot
     show_reblogs_in_public_timelines
     show_replies_in_public_timelines
-    spam_check_enabled
     trends
     trendable_by_default
     show_domain_blocks
@@ -59,7 +58,6 @@ class Form::AdminSettings
     enable_keybase
     show_reblogs_in_public_timelines
     show_replies_in_public_timelines
-    spam_check_enabled
     trends
     trendable_by_default
     noindex