Introduce proper HandlerFactory and reduce dependencies of RequestWorker

requestworker.cpp

@@ -66,9 +66,7 @@ Response RequestWorker::processRequest(const Request &r)
 		}
 	}
 
-	auto handler = createHandler(r.param("action"), *this->handlerConfig, *this->templ, *this->db, session,
-								 *this->urlProvider, *this->cache);
-
+	auto handler = handlerFactory->createHandler(r.param("action"), session);
 	try
 	{
 		Response response = handler->handle(r);