can now tell phabricator you trust an auth provider's emails (useful for Google OAuth), which will mark emails as "verified" and will skip email verification.

Summary: This is useful when you're trying to onboard an entire office and you end up using the Google OAuth anyway.

Test Plan: tested locally. Maybe I should write some tests?

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9150