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

Conflicts:
- `app/models/form/admin_settings.rb`:
  New setting added upstream. Ported it.
- `app/views/statuses/_simple_status.html.haml`:
  Upstream removed RTL classes. Did the same.
- `config/settings.yml`:
  New setting added upstream. Ported it.

app/presenters/instance_presenter.rb

@@ -29,7 +29,7 @@ class InstancePresenter
   end
 
   def domain_count
-    Rails.cache.fetch('distinct_domain_count') { Account.distinct.count(:domain) }
+    Rails.cache.fetch('distinct_domain_count') { Instance.count }
   end
 
   def sample_accounts