Add react-native-web support for the native example (JavaScript library)

[mateoguzmana]

Describe the feature

It would be great to have the option to generate the JavaScript library example directly supporting react-native-web. I noticed we have the option to either generate it for web with expo or native but there is no one that supports both (not sure if I'm missing something)

Motivation

I found myself adding the same webpack configuration to a couple of libraries I wanted to add react-native-web support that were created with bob. It would be cool to have the option.

We could have a third option called Native and web and then adding an extra webpack/react-native-web configuration for that one.

I'm happy to submit a PR for this