Summary:
This Diff moves all the Flipper.rb related setup in the cocoapods scripts to a dedicated script.
It also removes the not needed dummy files and add tests for flipper.
## Changelog
[iOS][Internal] - Extract Flipper setup in a separate file and add tests
Reviewed By: cortinico
Differential Revision: D36129808
fbshipit-source-id: 5446203a69b527146c893aa9611e98688e20b778