[Feature] Use Apple Watch for second screen systems

[JoeMatt]

Using ScreenShare framework, it's possible to bounce images to another device. Example,

https://github.com/anirban261491/Screen-sharing-iOS

The idea would be to use another watch/tvos/ios/macos device as a second screen for systems that have some use for it,

1. Dreamcast VMU screen
2. PS2 dual screen mode (PS TV)