Add retention policy for cached content and media (#19232)

app/lib/vacuum/system_keys_vacuum.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class Vacuum::SystemKeysVacuum
+  def perform
+    vacuum_expired_system_keys!
+  end
+
+  private
+
+  def vacuum_expired_system_keys!
+    SystemKey.expired.delete_all
+  end
+end