Refactor of PointerController

Abstracted logic that applies to all pointer types into general
PointerController class and moved implementation of logic specific
to the mouse cursor and touch spots to MouseCursorController and
TouchSpotController, respectively.
Test: Pixel 3XL device, atest PointerController_test, compile

Change-Id: Ia5825c37ca75951cc8bcd7d5102c986bd957e69f