Add Reviewable model concern (#31152)

app/models/concerns/reviewable.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Reviewable
+  extend ActiveSupport::Concern
+
+  def requires_review?
+    reviewed_at.nil?
+  end
+
+  def reviewed?
+    reviewed_at.present?
+  end
+
+  def requested_review?
+    requested_review_at.present?
+  end
+
+  def requires_review_notification?
+    requires_review? && !requested_review?
+  end
+end