Pointer icon refactor for stylus (base)

When PointerChoreographer is enabled, PointerChoreographer can
create multiple StylusPointerControllers for each stylus device.
A StylusPointerController is created when the corresponding stylus
sends the first hover event. It can show and hide a hover pointer
on the associated display.

Test: atest libinputservice_test
Bug: 293587049
Change-Id: I208f09f0e0f73a6396d60f5b2bd0242dddd3c66b