Summary:
Ref T4038. This adds everything except the actual pushing part for mirrors.
This isn't the most beautiful or sophisticated UI, but I want get the authoritative repositories self-hosted and get users beta-ing hosting as soon as possible. We can do transactions, etc., later on.
Test Plan: See screenshots.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T4038
Differential Revision: https://secure.phabricator.com/D7632
