Summary: Ref T5089. Adds a `security.require-multi-factor-auth` which forces all users to enroll in MFA before they can use their accounts.
Test Plan:
Config:
{F159750}
Roadblock:
{F159748}
After configuration:
{F159749}
- Required MFA, got roadblocked, added MFA, got unblocked.
- Removed MFA, got blocked again.
- Used `bin/auth strip` to strip MFA, got blocked.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T5089
Differential Revision: https://secure.phabricator.com/D9285
