Add alarm + media/other to NotifManager.Policy

Alarm and media/system/other policies added to be able to toggle
filtering of alarm and media sounds for ZenMode/DND.

Bug: 63077372
Test: runtest -x frameworks/base/services/tests/notification/src/com/android/server/notification/ZenModeHelperTest.java
Change-Id: I256782af00ad736c1aebdb96f9400d66ebb64a15