Native Fullscreen Video on Android / Convenience cross-platform fullscreen video component

[brentvatne]

Moved from: https://github.com/expo/expo-sdk/issues/39

@gkufera has some ideas for what to do here and it's on the roadmap.

[gkufera]

Note that you can create a fullscreen player that works on both platforms by making a Video component that fills the entire screen. This issue is just to either create an android equivalent of the iOS fullscreening available through the imperative API on Video, or a convenience cross-platform fullscreen video component implemented with Video.

[anp]

Closing in favor of https://expo.canny.io/feature-requests/p/fullscreen-video-on-android