run-android|run-ios do not support RNTester out of the box

[grabbou]

Instructions to run RNTester recommend running Gradle / opening Xcode in order to run the app. We should add support for using the CLI, which will make it faster and easier to run RNTester and check when releasing new versions.

The biggest issue is in the detection mechanism that are inside run-android and run-ios (that are quite dumb).

[grabbou]

While doing it, rename --root in run-android to be less confusing (ideally, make it like the run-ios)

[grabbou]

iOS part is being worked on in #287

[grabbou]

@dulmandakh would you be able to explain why some Android projects have android/gradlew and others have android/app/gradle (RNTester)? Trying to handle both cases when doing run-android and I am a bit lost here.

[thymikee]

AFAIK this is done.