Spotify Discover Page Redesign

Spotify is a really beloved app that I get to stare at all day long, so it came naturally to me to do some exploration with the panel organization and introductory slider.

Some key things I was experimenting with:
- Nesting L1 sidebar navigation and adding better visual cues (spotify please do this)
- Injecting more colour by pulling gradients from cover art
- Moving friends feed away from being permalocked to right sidebar
- Optimizing for keyboard/tv nav