Settings: New DND access settings page.

- New advanced notification settings subpage for managing apps
   that have requested the ability to manage notification policy.
 - Create new "Advanced" section at the bottom of notification settings
   for this and the existing Notification access settings page.

Bug: 18298798
Change-Id: Ib415e634980d37d6492799f67a6619700ee2a01c

src/com/android/settings/Settings.java

@@ -91,6 +91,7 @@ public class Settings extends SettingsActivity {
     public static class NotificationStationActivity extends SettingsActivity { /* empty */ }
     public static class UserSettingsActivity extends SettingsActivity { /* empty */ }
     public static class NotificationAccessSettingsActivity extends SettingsActivity { /* empty */ }
+    public static class ZenAccessSettingsActivity extends SettingsActivity { /* empty */ }
     public static class ConditionProviderSettingsActivity extends SettingsActivity { /* empty */ }
     public static class UsbSettingsActivity extends SettingsActivity { /* empty */ }
     public static class TrustedCredentialsSettingsActivity extends SettingsActivity { /* empty */ }