R1:a06715ccdddc

Allow repository short names to be used as identifiers

Summary:
Ref T4245. This allows `bin/repository update bread` to work, in addition to `rBREAD`, `R123`, `123`, `BREAD`, etc., if a repository has a short name set.

This primarily affects CLI commands (like `bin/repository`) and Conduit API calls. It has no normal user-facing impact.

Test Plan: Ran `bin/repository update bread` and such.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.