Refactor Plugin + add missed typing

[yjose]

This PR added a simple Expo app demo to test the plugin within the repository. I also had the opportunity to test the refactoring done in #34, but it appears that it is not functioning in a real-world application. The plugin is not adding a badge to the app icon.

This is a return to the old behavior until we find the best option to fix it.

For people want to test here is how

1. Clone the branch.
2. Run pnpm install.
3. Execute pnpm run prebuild-demo.
4. Check the native folder inside the demo for icons with badges at demo/ios/demo/Images.xcassets/AppIcon.appiconset/[email protected] and demo/android/app/src/main/res.
5. If you want to try the withDangerMod implementation, replace the function inside app.plugin.ts with an async function and test again.

#31

[yjose]

@janwiebe-jump 👀