[Media] Adds card "guts" component.

Please refer to the screenshot at screen/8GPevR3xZ5tCC9o

Bug: 397989775
Test: tested in testbed app with fake data, see b/397989775 #comment2 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: I300aa28f1cb55c031286e47e5c7e771ab218e861