KubeEdge Cloud Stream and Edge Stream DoS from large stream message

KubeEdge is an open source system for extending native containerized application orchestration capabilities to hosts at Edge. Prior to versions 1.11.1, 1.10.2, and 1.9.4, the Cloud Stream server and the Edge Stream server reads the entire message into memory without imposing a limit on the size of this message. An attacker can exploit this by sending a large message to exhaust memory and cause a DoS. The Cloud Stream server and the Edge Stream server are under DoS attack in this case. The consequence of the exhaustion is that the CloudCore and EdgeCore will be in a denial of service. Only an authenticated user can cause this issue. It will be affected only when users enable `cloudStream` module in the config file `cloudcore.yaml` and enable `edgeStream` module in the config file `edgecore.yaml`. This bug has been fixed in Kubeedge 1.11.1, 1.10.2, and 1.9.4. As a workaround, disable cloudStream module in the config file `cloudcore.yaml` and disable edgeStream module in the config file `edgecore.yaml`.