Add a "View Repository" button to the repository manage UI

Summary:
Ref T10923. We sort of dead-end new users creating repositories right now, by dumping them into the manage UI without an obvious way forward.

You can click the crumb to get to the repository, but by default it will say something like R1 which isn't very obvious.

Add a more obvious navigational link to get to the main view.

Test Plan:

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10923

Differential Revision: https://secure.phabricator.com/D15889