Merge commit 'be991f1d18006a4820c1e9ca6625bf2bd2bfedac' into glitch-soc/merge-upstream

Conflicts:
- `app/models/form/admin_settings.rb`:
  Upstream added the notion of overriden settings, while we had extra code for
  pseudo-settings (only used to combine flavour and skin in a single select
  field).
  Ported upstream changes.
- `config/i18n-tasks.yml`:
  Upstream added `simple_form.overridden` to `ignore_unused`,
  we had `simple_form.glitch_only`.
  Added `simple_form.glitch_only` as well.

app/helpers/authorized_fetch_helper.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module AuthorizedFetchHelper
+  def authorized_fetch_mode?
+    ENV.fetch('AUTHORIZED_FETCH') { Setting.authorized_fetch } == 'true' || Rails.configuration.x.limited_federation_mode
+  end
+
+  def authorized_fetch_overridden?
+    ENV.key?('AUTHORIZED_FETCH') || Rails.configuration.x.limited_federation_mode
+  end
+end