Storybook added to project

Big addition: We've added Storybook to the project!

React Storybook is a UI development environment for your React components. With it, you can visualize different states of your UI components and develop them interactively.
It runs outside of your app. So you can develop UI components in isolation without worrying about app specific dependencies and requirements.

We've also made changes to the README, switching npm to yarn in the installation instructions. If you want to test out storybook run yarn storybook