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

i18n/en.json

@@ -151,6 +151,22 @@
     "id": "api.api.render.error",
     "translation": "Error rendering template %v err=%v"
   },
+  {
+    "id": "wsapi.user.init.debug",
+    "translation": "Initializing user WebSocket API routes"
+  },
+  {
+    "id": "wsapi.system.init.debug",
+    "translation": "Initializing system WebSocket API routes"
+  },
+  {
+    "id": "wsapi.status.init.debug",
+    "translation": "Initializing status WebSocket API routes"
+  },
+  {
+    "id": "wsapi.webrtc.init.debug",
+    "translation": "Initializing webrtc WebSocket API routes"
+  },
   {
     "id": "api.auth.unable_to_get_user.app_error",
     "translation": "Unable to get user to check permissions."