Add management of delivery availability in Federation settings (#15771)

* Add management of delivery availavility in Federation settings

* fix translate

* Remove useless object creation

* Fix DeepSource issue

* Add shortcut for all

* Fix DeepSource(skipcq)

* Change 'remove' to 'clear'

* Fix style

* Change class method name (exhausted_deliveries_key_by)

app/policies/delivery_policy.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class DeliveryPolicy < ApplicationPolicy
+  def clear_delivery_errors?
+    admin?
+  end
+
+  def restart_delivery?
+    admin?
+  end
+
+  def stop_delivery?
+    admin?
+  end
+end