Use callsigns, cards on repository lists

Summary: Minor, adds the Callsign and changes to cards view when listing repositories.

Test Plan: Reload sandbox list of repositories, see new items.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8036