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

Conflicts:
- app/views/admin/settings/edit.html.haml:
  Conflict due to how the theming settings change.

app/controllers/admin/settings_controller.rb

@@ -10,7 +10,7 @@ module Admin
       site_description
       site_extended_description
       site_terms
-      open_registrations
+      registrations_mode
       closed_registrations_message
       open_deletion
       timeline_preview
@@ -33,7 +33,6 @@ module Admin
     ).freeze
 
     BOOLEAN_SETTINGS = %w(
-      open_registrations
       open_deletion
       timeline_preview
       show_staff_badge