Added volume control to Notification Profiles.

Allows the system volume settings to be adjusted when switching to a new profile.
This should cater for some of the apps which don't use the Notifiation Manager or
Ringtome Manager for their alerts. I should also allow a "Total Silence" kind of
profile.

Change-Id: Ib9a4b771cb39797c65f81ef09257d18c2ab94611