Building a plugin for Messenger Co Presence

Summary:
Created a plugin from   https://www.internalfb.com/intern/staticdocs/flipper/docs/tutorial/intro

The plugin allows us to look at various signal events and help debug issues for messenger copresence with different protocols (upi or gqls)

Differential Revision: D28548194

fbshipit-source-id: 5f5063dc5bc1dbf282bd327907003301836f3698

desktop/static/icons.json

@@ -609,5 +609,8 @@
   ],
   "commercial-break-usd": [
     16
+  ],
+  "friends-engagement": [
+    16
   ]
-}
+}