Use GID "wakelock" to control access to kernel wakelock

* Added new kernel GID named "wakelock" (AID_WAKELOCK = 3010)
* Changed the group access for /sys/power/wake_lock and
  /sys/power/wake_unlock from "system" to "wakelock"
* Added "wakelock" to the list of groups for the healthd process/service

Bug: 25864142
Change-Id: Ieabee9964cccec3107971a361a43aa9805164aa9