R1:2c435433e0db

Start fleshing out PhabricatorAuthProviderViewController

Summary:
Ref D20645. Start making this view a little more useful:

{F6573605}

Test Plan: Mk. 1 eyeball

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D20646