Add encoding information to "repository.query"
Summary: Ref T7604. Add encoding information to the repository.query #conduit query.
Test Plan: Changed repository encoding from the UI and saw the encoding returned by the Conduit call.
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T7604
Differential Revision: https://secure.phabricator.com/D12992