Add CORS support to thrift end points.

Add CORS support for thrift end points. Added a command line option to explicitly enable that
support since this may a potential security issue and we may not want to enable it in production.

Testing Done:
Local laptop. Attached screenshot.
Called the API from another JS app and was able to make a successful $http.post().

Bugs closed: AURORA-390

Reviewed at https://reviews.apache.org/r/21497/