Google auth v1 (#2818)

* Google Auth  [wip] [ci skip]

* "No Metabase account exists for this Google account" screen 

* Single Sign On Settings Page [WIP] 

* Google Auth v1 

* update login layout

* add setup instructions

* add google logo for google account signups

* clean up sso form layout

* Merge branch 'master' into google-auth [ci skip]

* Fix Google Auth button not showing up after initial load 

* Fix bug when creating session for user with no last_login 

* Organize google auth backend code a bit 

* Lots of tests for Google Auth 

* Add Save Button to Google Auth settings page 

* Use onChange instead of onBlurChange 

* Make "save changes" button say "changes saved" after save 

* adjust user settings for managed accounts

* Ensure we clear GA creds if GA login fails

* tweak password reset email

* owned google sign in button

* use var

* Cleanup some random legacy Angular junk

* Keep Redux and AppState currentUser in sync, fixes login issue

* render() should have side-effects! Fixes $digest errors on logout

* Test fixes 

* fix checkbox

* cleanup

* remove unused import