Load default zen rules from xml

Change-Id: Ic82b5d048346127847685791164f0decc8b61f92
Fixes: 114200998
Test: atest frameworks/base/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
Test: atest frameworks/base/services/tests/uiservicestests/src/com/android/server/notification/ZenModeHelperTest.java
5 files changed