Use react-native-test-app for example

[Naturalclar]

I'd like to simplify the example directory by using https://github.com/microsoft/react-native-test-app

Replace the current example repository with a project created by yarn test-init-app (a command in react-native-test-app)

Follow the instruction in the react-native-test-app document to setup examples for iOS/Android/MacOS/Windows

[Cor4zon]

I can take that issue. Please assign it to me

[Naturalclar]

@Cor4zon Sure!