Create a new apps page for silky home

- Change recent apps to the list view.
- Remove Conversations, Notifications and Permission manager.
- Remove Wireless emergency alerts and Special app access.
- Show App info preference if there's no recent apps.
- Show general category with recent apps.
- Use this page as the new apps entry on homepage for silky home.
- Make old apps page unsearchable when silky home is enabled.
- Exported new apps page in AndroidManifest.

Bug: 168166015
Bug: 174964405
Test: robotest & visual
Change-Id: I50d35a9d4723612214fce45a9e129fc175bc6831

src/com/android/settings/Settings.java

@@ -251,4 +251,8 @@ public class Settings extends SettingsActivity {
      */
     public static class MediaControlsSettingsActivity extends SettingsActivity {}
 
+    /**
+     * Activity for AppDashboard.
+     */
+    public static class AppDashboardActivity extends SettingsActivity {}
 }