Update app to React 18 + Chakra 2 + Framer-Motion 11 (#83)

* Update app to React 18 + Chakra 2 + Framer-Motion 11

Animation support needs a newer Framer-Motion version which pulls in newer
React which again is only supported by newer Chakra.

* Switch to `ReactDOM.createRoot`

The old `ReactDOM.render` function is deprecated in React 18.

See: https://reactjs.org/link/switch-to-createroot

Author: ntninja