Listen to rotary input events and report them to FocusEventDebugView.

A system setting key was implemented for showing rotary input
(temporarily only by logging it). To show this input, use the following
command:

adb shell settings put system show_rotary_input 1

Bug: 286086154
Test: manual
Change-Id: If8f817796eefc12874a00f41549e555e8e774b25