Summary:
This diff adds upload and download logic for certs. It makes changes on both Flipper Client and Desktop side. With this we enable cert exchange through WWW.
Next Diffs:
1) Add Flipper state in cert provider for more debug data
2) Tests
Reviewed By: jknoxville
Differential Revision: D23092706
fbshipit-source-id: e576253606b64b62848b70203db7e09a3bd77fd9
f626925443