[Developer Experience Refactor - Frontend] - using the "barrel file" approach for more explicit coupling on the frontend

[nspilman]

The purpose of this refactor is to make the coupling on the frontend more explicit. General rules with this setup -

• We're always either importing from a child component or from root. this allows us to move whole component trees around without breaking any dependencies
• everything is named exported and export from the directory level via the index.ts file
• code that is only used in one place lives in the directory it's used

https://www.loom.com/share/8e2660792dda49e09804a02aafc24754