feat: setup package to use exports keyword and expose app.plugin.js

[gladiuscode]

Goal

This PR updates the library configuration to:

1. Properly expose both CommonJS and ESM modules through the exports keyword;
2. Instruct react-native-builder-bob to emit both modules and typescript types so that metro bundler can find them;
3. Properly expose the app.plugin.js file so that Expo can find the plugin and use it in the CGN setup;

Thanks again to the community for the help.

More here: callstack/react-native-builder-bob#837