Improve Project Navigator file tree

Issues with the current implementation:
- _a lot_ of duct tape to fix performance issues
- confusing communication between desktop and web
- no clearly defined data structures for files and directories
- UI is difficult to style based on the strange component structure, along with reliance on scss

I'm in the process of making a separate npm module for just rendering and controlling a file tree view. Seems like a cohesive, reusable chunk that others would be interested, and more than anything I want it out of our codebase :P