Rearrange a few settings into System category page.

- Use activity-alias to define which activity shows up in what category.
  We choose activity-alias because it creates a reference to UI we need
  without having to define a new set of intent-filter and/or category
  keys. This reduces maintainence in the long run. We should merge
  metadata from activity-alias into targetActivity when cleaning up.

- Created new System dashboard activity that hosts all system category
  tiles dynamically, and a static tile for checking system update.

Bug: 31781480
Test: manual
Test: make RunSettingsRoboTests -j40
Change-Id: Ia2d762e3e1aebd17423a395c5e6c286dc3326492

src/com/android/settings/dashboard/DashboardFeatureProviderImpl.java

@@ -21,6 +21,7 @@ import android.content.Context;
 import com.android.settingslib.drawer.CategoryKey;
 import com.android.settingslib.drawer.CategoryManager;
 import com.android.settingslib.drawer.DashboardCategory;
+import com.android.settingslib.drawer.Tile;
 
 import java.util.List;
 
@@ -48,8 +49,18 @@ public class DashboardFeatureProviderImpl implements DashboardFeatureProvider {
         return mCategoryManager.getTilesByCategory(mContext, CategoryKey.CATEGORY_HOMEPAGE);
     }
 
+    @Override
+    public DashboardCategory getTilesForSystemCategory() {
+        return mCategoryManager.getTilesByCategory(mContext, CategoryKey.CATEGORY_SYSTEM);
+    }
+
     @Override
     public List<DashboardCategory> getAllCategories() {
         return mCategoryManager.getCategories(mContext);
     }
+
+    @Override
+    public int getPriorityGroup(Tile tile) {
+        return tile.priority / 100;
+    }
 }