AMP Compatible App Banner

This will be very helpful for anyone with an app who wants to break their users out of Google's AMP viewer.

Using Universal Links for it is helpful — other AMP banners I've seen so far (Reuters, etc [1]) just redirect users to the App Store even when the app is installed...a little bit frustrating.

1. https://www.google.com/amp/mobile.reuters.com/article/amp/id...

Wow. Very cool.