R1:727c326e2ea5

Complete missing bits of Google OAuth2 provider

Summary: Added support for profile images and URLs.

Test Plan: Looked at /settings/panel/oauth-google/, refreshed profile picture, click profile URL, saw correct profile.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4556