Add TabletopModeController in WMShell Populate the resource config that defines the horizontal fold and together with the device posture to determine if the foldable device is in tabletop mode or not. Bug: 260871991 Test: atest WMShellUnitTests:TabletopModeControllerTest Change-Id: I7878ec9ef95be39c2f1dc7ada7e7c871a018fa6e