Standalone NPM packages and React Native support

[bvaughn]

Resolves #334

This PR does several things:

• Add version 4 react-devtools and react-devtools-core packages which support both React Native and e.g. Safari or iframe DOM usage.
• Replaces typed operations arrays with regular arrays in order to support Hermes. This is unfortunate, since in theory a typed array buffer could be more efficiently transferred between frontend and backend for the web extension, but this never actually worked properly in v8, only Spidermonkey, and it fails entirely in Hermes so for the time being- it's been removed.
• Adds support for React Native (paper renderer)
• Adds a style editor for react-native and react-native-web

[bvaughn]

Plowing ahead with this for now. Will follow up with some tweaks.