Spike: Redesign API and UI flow

[RyanRussell00]

Currently the API is serving all the React files from the build folder.
When the user first loads the site they see the React Homepage, then they log in, and when the login redirects, the page is from the api's static assets (build) folder.

Instead of doing this, we should try to only use the API for API requests and not serving pages. We can start this by having the Spotify redirect to the home page and handle the cookie logic right there.

This is gonna need some more research into how Express, Node, and React work together and will need a lot of playing around with.