Facebook messenger bot factor

[brendanheywood]

This is conceptually almost exactly the same as email / sms / telegram, but it has the added benefit of the messenger api being able to not just send a code which you type into the mfa form, but we could deliver an 'Allow' and 'Report' buttons directly in the message so you can approve it without copying anything. This uses the Postback Button api:

https://developers.facebook.com/docs/messenger-platform/reference/buttons/postback

https://developers.facebook.com/docs/messenger-platform/reference/webhook-events/messaging_postbacks/