feat: improve Example App

The Example app currently uses a Drawer(deprecated component) for navigation and a simple list based navigation to go each component showcase.
This could be improved by:
- replacing the drawer with a more modern UI like a modal sheet for global configuration of theme configuration
- adding a search functionality
- a main "sample" section when the user first opens the app showcasing a mix of different components like on https://oss.callstack.com/react-native-paper/ or https://material-foundation.github.io/material-theme-builder/