Log user level App Hibernation related atoms

At user level, we are logging one pushed atom when user level
hibernation state changed for a package; and one pulled atom with the
information of count of hibernating apps per user.

Bug: 186157912
Test: atest AppHibernationServiceTest
Test: run statsd_testdrive 10107, pulled data is correct;
Test: run statsd_testdrive 370. Run the hibernation job from cmd and see
correct pushed data

Change-Id: Ifdd04f6fffad9d425b0bfb39cba7bc2fcc993e5e