Support GESTURE_SENSOR input device type with GestureService

* The GESTURE_SENSOR input device type is meant to support touch sensors
  which are meant for gesture input only, very similar to a touchpad,
  but without the pointer capability.
* Define separate service to handle gestures from GESTURE_SENSOR device
  type.

Change-Id: Ib4f0aec98eeee1bea9ff7f842beed833f76cad3e