Introduce SingleKeyGestureDetector to PhoneWindowManager

The SingleKeyGestureDetector is used to detect the single key gesture
such as short press, long press or multi presses.

If the key has been handled by other policy, it should call 'cancel'
to reset all gesture states.

This patch refactor the power key and back key (long press behavior
enabled), it can detect below gestures:
- single press
- long press
- very long press
- multiple press ( <= 3)

Bug: 169058831
Bug: 127687575
Test: atest KeyEventTest SingleKeyGestureTests
Test: manual (short press power, long press power, double tap power)
Change-Id: I1c042e693e9844e30ce568eded7681fa4101daf9