`skip init` should set up a launch screen

[dfabulich]

Setting up a launch screen is kinda tricky platform-specific work. On iOS, you set up a UILaunchScreen Storyboard. On Android, you use the SplashScreen API.

It would be great if skip init provided a basic launch screen out of the box, which I could then edit in Xcode and Android Studio respectively.

[dfabulich]

If it would help, I'd be happy to file a PR on https://github.com/skiptools/skipapp-hello to include launch screens.

I assume y'all wouldn't be able to merge that as-is (because the skip CLI is closed source, right?) but it would give you material to copy and paste into your own code base…?