Update Auth for new UI

Summary: [WIP] Tossing this up for safety and to read through it. Need to test, update some of the other flows. This updates everything in Auth for new UI and modern conventions.

Test Plan: Loooots of random testing, new providers, edit providers, logging out, forgot password... more coming.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15550