Refactor suggestions

[BOLT04]

• We can use a React Fragment here instead of a div, like this

  <>
  <Switch>...</Switch>
  </>

• The file App.css is empty. Since we are using SCSS we could delete this and remove this import
• The App component doesn't use any state, so maybe we could simply use a functional component here.

What do you think @rossanodan?

[rossanodan]

@BOLT04 App.scss exists now and we can use it for global styles like font-family. The React.Fragment is a good idea, I'll fix it 👍