Load and map repository objects for remote URIs

Summary:
Ref T13546. Query and associate known Phabricator repositories to working copy remotes by normalizing and comparing URIs.

This primarily gives us access to "permanentRefRules" so we can tell which branches have published changes.

Test Plan: Ran "arc look remotes" in Git and Mercurial working copies, saw repositories map properly.

Maniphest Tasks: T13546

Differential Revision: https://secure.phabricator.com/D21377