R1:2d00f5683786

Use PHUIListItemView in ConpherenceThreadList

Summary: Fixes T12556 Uses more common components in ConpherenceThreadList by moving to PHUIListItemView. Reduces clutter by moving privacy into the header. Gets ride of "See More" double interchanges.

Test Plan:
I need to test this more, doesn't seem to auto-select top room any more, also might build a lipsum generator.

- Create lots of rooms with various policies
- Test clicking on policy object
- Click on different rooms
- Post in rooms
- Load up…