R1:3643fe1498f1

Use property tabs in Files

Summary:
See screenshots. Some simplifications:

- Tabbed and non-tabbed lists are now allowed to be mixed. We just make the non-tabbed lists permanent and put them on the bottom (e.g., image and audio data in Files).
- You can provide a tab name instead of an entire tab object and we'll build an object for you.
- We respect `setSelected()` on the tab objects now.

Test Plan: See screenshots.

Reviewers: chad, btrahan

Reviewed By: chad

CC: chad, aran

Differential…