Summary:
**Motivation**
Properly support long presses on the Apple TV remote, and also enable dev menu functionality on a real Apple TV device (shaking an Apple TV doesn't work 😄 )
**Test plan**
New example added to `RNTester`.
Closes https://github.com/facebook/react-native/pull/15221
Differential Revision: D5526463
Pulled By: javache
fbshipit-source-id: a61051e86bc82a9561eefc1704bed6b1f2617e05