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/serializers/rest/suggestion_serializer.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class REST::SuggestionSerializer < ActiveModel::Serializer
+  attributes :source
+
+  has_one :account, serializer: REST::AccountSerializer
+end