SysUI: Log lockscreen gestures

Log the following lockscreen gestures:
 * Swipe up to unlock
 * Swipe down to enter full shade
 * Tap in empty area (causing unlock hint)
 * Swipe to camera
 * Swipe to dialer
 * Tap on lock to lock device
 * Tap on notification, activating it

For swipe gestures, includes length and velocity where available.

Bug: 18767135
Change-Id: Ib2c535e3a9d2b378f5a2a0a00c2be3fd916554ac