Summary:
This commit moves all the turbo module files for Android to Github.
Note that gradle build is not yet enabled.
Sample Turbo Modules will be added in a later commit.
Other missing features
- Support for `CxxModule`
- Remove usage of folly::dynamic for arguments and result conversion
- Support for Promise return types.
Reviewed By: mdvacca
Differential Revision: D13647438
fbshipit-source-id: 5f1188556d6c64bfa2b2fd2146ac72b0fb456891