Add a setting to disable all notification email
Summary: Ref T5861. Adds an option to opt out of all notification email. We'll still send you password resets, email verifications, etc.
Test Plan:
- Added unit tests.
- With preference set to different things, tried to send myself mail. Mail respected preferences.
- Sent password reset email, which got through the preference.
Reviewers: btrahan, chad
Reviewed By: chad
Subscribers: rush898, epriestley
Maniphest Tasks: T5861
Differential Revision: https://secure.phabricator.com/D10237