Move WebSocket API to it's own package and add websocket v4 endpoint (#5881)

wsapi/api.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package wsapi
+
+import (
+	"github.com/mattermost/platform/app"
+)
+
+func InitRouter() {
+	app.Srv.WebSocketRouter = app.NewWebSocketRouter()
+}
+
+func InitApi() {
+	InitUser()
+	InitSystem()
+	InitStatus()
+	InitWebrtc()
+
+	app.HubStart()
+}