Optimise React for production builds

[gmarty]

Babel react conserves the propTypes of components (which is both expected and wanted).
But in production mode they add no benefits to the components so we want to remove them.

Let's enquire and see if it's a common practice in the React world and if there are already tools to do that.

[gmarty]

It turns out there are a couple more optimisations we can do to make more efficient production build of React:
https://medium.com/doctolib-engineering/improve-react-performance-with-babel-16f1becfaa25

[gmarty]

We also need to use the .min.js versions of React scripts for better performance in production.