We used to convert Keyevents into AccessibilityEvents, and converted
them back in RotaryServiceBase. But now with the new CarInputManager
APIs, we no longer need to do that.

This CL also introduces a class for logging.

Fixes: 152441772
Fixes: 152630987
Test: manual
adb shell cmd car_service inject-rotary
adb shell cmd car_service inject-key 280
adb shell cmd car_service inject-key 23

Change-Id: I3ab726ad2a23c35e02e6c481b5ab81736374d7ce