Implement payments

[maciekmm]

https://developers.facebook.com/docs/messenger-platform/changelog
https://developers.facebook.com/docs/messenger-platform/complete-guide/payments
https://developers.facebook.com/docs/messenger-platform/send-api-reference/buy-button
https://developers.facebook.com/docs/messenger-platform/send-api-reference/webview

Introduced Payments in beta! Request access through this form.
For native payments use new Buy Button along with Generic template
For payments from the web see Webviews and Extensions

[leonardogcsoares]

Will try to tackle this for you! =D

[maciekmm]

@leonardogcsoares Hello! Are you still on it? :>

[katomaso]

Most likely not on it anymore