Summary:
Due to Thrift design of "include" statements in fbcode the thrift structures has to be contained in folders that are identical to the folder layout inside fbcode.

This diff changes the folder layout on Cargp.toml files and in fbcode_builder, there will be a next diff that changes this for ShipIt as well.

Reviewed By: ikostia

Differential Revision: D22208707

fbshipit-source-id: 65f9cafed2f0fcc8398a3887dfa622de9e139f68