Create React App Cleanup

Some basic cleanup steps after creating a new project with create-react-app.

1. Erase everything in src/App.css but leave the file in place
2. Delete src/index.css and the import in src/index.js
3. Delete src/logo.svg and the import in src/App.js
4. Remove everything inside the App component div in src/App.js
5. Create a components folder inside src/