feat: implement server-initiated heartbeat in msgGateway module (#2404)

* feat: implement send ping msg when platform is web in gateway.

* add context life cycle control.

* feat: implement heartbeat logic in msggateway.

* update heartbeat logic.

* update to correct method name and comment.

* update initiate heartbeat logic.

* rename ws_server

* update writePingMsg logic

* update log level to warn.

internal/msggateway/constant.go

@@ -53,6 +53,9 @@ const (
 	// Time allowed to read the next pong message from the peer.
 	pongWait = 30 * time.Second
 
+	// Send pings to peer with this period. Must be less than pongWait.
+	pingPeriod = (pongWait * 9) / 10
+
 	// Maximum message size allowed from peer.
 	maxMessageSize = 51200
 )