React Native bundle step

Bitrise step for bundling React Native apps

Calls react-native bundle.

Options:

• binary_path specify custom path to the react-native, like {binary_path}/react-native. Defaults to react-native
• platform specify the platform(android/ios)
• --dev sets DEV flag to true
• --root add another root(s) to be used in bundling in this project
• --assetRoots specify the root directories of app assets
• --out specify the output file
• --url specify the bundle file url
• options any additional options separated by a space.