Conduit file upload method that takes in the files content hash and name. Returns the file phid if successful. Updates to phutil library map.
Summary: Conduit method to upload a a new file using a hash
Test Plan: Try uploading a file using its content hash
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D4899