Draft: listview updates

Draft warning:
Currently this branch contains lots of experiments (like dumping lots of .node files into your cwd and spamming stderr), so use at your own risks.

Things this MR does so far:

• Attempt to fix #2971 (closed)

• Add a ::focus-position and ::focus-item property to track the item with keyboard focus, and to set that item - which includes scrolling to it.