Added NetworkSourceContainers Flipper Plugin (Desktop) 1/3

Summary:
Added Flipper plugin.

Initial scaffolding for both iOS and JS
javascript code

Reviewed By: apadalko

Differential Revision: D37612499

fbshipit-source-id: a0a0ef596ef39f1d0bfe978767748c8fc3840d7a

desktop/static/icons.json

@@ -638,5 +638,8 @@
   ],
   "friend-except": [
     16
+  ],
+  "app-instagram": [
+    16
   ]
-}
+}