OAuth - add concept of "trusted" clients that get auto redirects

Summary: Fixes T7153.

Test Plan:
used bin/auth trust-oauth-client and bin/auth untrust-oauth-client to set the bit and verify error states.

registered via oauth with bin/auth trust-oauth-client set and I did not have the confirmation screen
registered via oauth with bin/auth untrust-oauth-client set and I did have the confirmation screen

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7153

Differential Revision: https://secure.phabricator.com/D11724