flipper UI add compose to message

Summary:
Using this diff as baseline for fblite composer.
Demo in this post https://fb.workplace.com/groups/503571760094149/permalink/934762916975029/

## Next
* UI
* Add binary buffer (clone/re-send)
* Support multiple messages as flow
* Persistance
* More feedbacks from post

{F238376954}

Reviewed By: timur-valiev

Differential Revision: D21701994

fbshipit-source-id: 020733034968acb5c02a1f79bfc256a1a13d6ef8

desktop/static/icons.json

@@ -87,7 +87,8 @@
     8
   ],
   "compose": [
-    12
+    12,
+    16
   ],
   "copy": [
     12
@@ -412,5 +413,14 @@
   ],
   "circle": [
     12
+  ],
+  "comment-swish": [
+    16
+  ],
+  "direct": [
+    16
+  ],
+  "plus": [
+    16
   ]
 }