[13/n] Create Overrides and Policy for App Compat Camera

Create AppCompatCameraPolicy and the related Overrides classes
to encapsulate app compat camera logic.

Flag: EXEMPT refactor
Bug: 346253439
Test: atest WmTests:LetterboxUiControllerTest
Test: atest WmTests:DisplayRotationCompatPolicyTests
Test: atest WmTests:CameraCompatFreeformPolicyTests
Test: atest WmTests:AppCompatOrientationOverridesTest
Test: atest WmTests:ActivityRefresherTests

Change-Id: Iff31b0c76e184464e52424664c7b7f1ac9b190cc