server api支持获取频道信息，销毁频道信息，销毁机器人功能

broker/src/main/java/io/moquette/spi/IMessagesStore.java

@@ -133,6 +133,7 @@ public interface IMessagesStore {
 
     WFCMessage.Robot getRobot(String robotId);
     void addRobot(WFCMessage.Robot robot);
+    void destroyRobot(String robotId);
 
     ErrorCode getUserInfo(String fromUser, List<WFCMessage.UserRequest> requestList, WFCMessage.PullUserResult.Builder builder);