Directory view: Bookmark listing

[peterhil]

Show all categories and bookmarks alphabetically on left and right pane initially.

Left side:

• [x] Show categories on the left side
• [x] Show main categories first

Right side:

• [ ] Show selected category contents on the right side
• [ ] Scroll to (first) selected category on the left side when selecting bookmarks on the right side

Select and unselect categories

• [ ] Implement caching service for all bookmarks
  • [ ] Initialize service with all bookmarks
  • [ ] Update cache on bookmark modifying events
• [ ] Select and unselect categories by single click and update the right side content accordingly
  • [ ] Split left pane and right pane into separate tags and communicate with events
  • [ ] Observe events from these tags with Kefir and update views accordingly