* Tiny change to the CSS for a quick fix

Simply making sure the target of the CSS rules are always list-items found in the nav and not just any list-items (such as those identical list-items used in the panel queue).

* Tiny CSS change to fix panel queue issue

* Made the open/closed indicator a pseudo element
Added a hover state, and support for nested folders (up to 10 levels deep)
Moved all the styles to /src/styles/app.scss
Imported the styles into the app.tsx file
Deleted the extra app.tsx which was in the root.
Added way too many comments, but reabability is king imo.

* Cleanup - removed old compiled js file from the root.