[Dynamic Home] Make a new page for all top level settings

Since we are moving conditionals/suggestions to a different place, there
is no need to use DashboardSummary to display top level settings any
more. We can simplify a lot of code for top level settings and reduce it
to a standard DashboardFragment.

- Create a new DashboardFragment + xml for all top level internal items
- Add a PreferenceController to provide summary for Network & internet
  item.
- Mark a bunch of things deprecated for future work.

Bug: 110405144
Test: robotests
Change-Id: I9f778777131c28eb836b722e089e026a59f5ddc6

src/com/android/settings/network/NetworkDashboardFragment.java

@@ -149,6 +149,7 @@ public class NetworkDashboardFragment extends DashboardFragment implements
         return 0;
     }
 
+    // TODO(b/110405144): Remove SummaryProvider
     @VisibleForTesting
     static class SummaryProvider implements SummaryLoader.SummaryProvider {