Server: Categorize functions

Redis/Service functions declared as STATIC to avoid unneded calls
but it's really questionable if they trully are

server/extension/sql/100_routing_helper.sql

@@ -63,4 +63,4 @@ RETURNS cdb_dataservices_server.simple_route AS $$
     raise Exception('Error trying to calculate mapzen routing')
   finally:
     quota_service.increment_total_service_use()
-$$ LANGUAGE plpythonu SECURITY DEFINER;
+$$ LANGUAGE plpythonu SECURITY DEFINER STABLE PARALLEL RESTRICTED;