Objective

A customizable navigation sidebar that can alternate between static menu items and automatically generated list of pages at the current level.

### Tasks
- [ ] Browse mode
- [x] Static mode
- [x] Static - Add / Edit / Delete / Rearrange Items
- [x] Static - Per path (exact / starting with) navigation items
- [x] Static - Nested Menus
- [ ] Admin - View list of all navs