[LivePicker 3/n] Enable LivePreviewFragment

Add support for delete and settings actions and hook up
LivePreviewFragment (disabled for now)

There's still redundancy between ImagePreviewFragment and
LivePreviewFragment, follow up CLs will clean this up.

Bug: 141391722
Change-Id: I14afa659919b8a61959706fa23a049f90dc6536b
9 files changed