Plugin Directory: Release Confirmation: Require 2FA instead of email verification

[dd32]

When a user has 2FA setup, we should rely upon that instead of email.

This is more secure, and for those who are using Keys, likely more streamlined.

This is a work in progress, and requires a few more steps.

See https://meta.trac.wordpress.org/ticket/7704

This is reliant upon https://github.com/WordPress/wporg-two-factor/pull/283