Add side loaded listener and controller

- Add SideLoadedAppController as a SysUI class to kick off the
sideloaded app tracking.
- Add SideLoadedAppStateController to manage the state of sideloaded
apps. This class is just a wireframe and will be filled in the following
cls.
- Add SideLoadedAppListener to listen for stack changes and notify the
state controller when the sideloaded apps state changes.
- Add unit test for SideLoadedAppListener

Bug: 154263570
Test: atest (All tests in CarSystemUITests)

Change-Id: I8d2b9b3d224017d9a51e2590a1aae0a9a265f7c3