[Media] Card.

Includes the UI for a single media card

- Each card contains a SceneTransitionLayout (STL) so it can "morph" as
  the presentation style of the card changes. This is what takes care of
  animating the card layout and its elements.
- Note that the normal card, includes logic to show and hide the guts
  while the dual shade version doesn't.

Bug: 397989775
Test: tested in testbed app with fake data, see b/397989775#comment4 for a screen recording of the entire thing in action in the compose gallery app
Flag: EXEMPT none yet, code is currently unused
Change-Id: I2727213f4dab819614aa2dfde80f6ece50882dca