Server-side controls for auto-revoke

This adds DeviceConfig(kill skitch + configurable intervals)
and server-side logging.

Test: for DeviceConfig:
  $ adb shell cmd device_config put permissions auto_revoke_check_frequency_millis 4242
  - ensure frequency changed using logcat
for Logging:
  $ m statsd_testdrive && out/host/linux-x86/bin/statsd_testdrive -p com.google.android.permissioncontroller 170
  - trigger auto-revoke job and ensure data printed by command above
Change-Id: Ibbf106bdc758aadcef1b606381765596f57d9a7c