[5/n] Create AppCompatCapability

Create the AppCompatCapability class and move the code from
LetterboxUiController about app compat features depending on
per app overrides.
At this stage the code related to orientation overrides is
still in LetterboxUiControllerTest.

Flag: EXEMPT refactor
Bug: 345156325
Test: atest WmTests:LetterboxUiControllerTest
Test: atest WmTests:SizeCompatTests

Change-Id: I212b24df6abf69a86e8551682966dca3fe26063e