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/views/admin/settings/edit.html.haml

@@ -101,9 +101,6 @@
   .fields-group
     = f.input :show_replies_in_public_timelines, as: :boolean, wrapper: :with_label, label: t('admin.settings.show_replies_in_public_timelines.title'), hint: t('admin.settings.show_replies_in_public_timelines.desc_html')
 
-  .fields-group
-    = f.input :spam_check_enabled, as: :boolean, wrapper: :with_label, label: t('admin.settings.spam_check_enabled.title'), hint: t('admin.settings.spam_check_enabled.desc_html')
-
   %hr.spacer/
 
   .fields-group