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/DashboardFeatureProvider.java

@@ -16,6 +16,7 @@
 package com.android.settings.dashboard;
 
 import com.android.settingslib.drawer.DashboardCategory;
+import com.android.settingslib.drawer.Tile;
 
 import java.util.List;
 
@@ -34,8 +35,20 @@ public interface DashboardFeatureProvider {
      */
     DashboardCategory getTilesForHomepage();
 
+    /**
+     * Get tiles (wrapped in {@link DashboardCategory}) for system category.
+     */
+    DashboardCategory getTilesForSystemCategory();
+
     /**
      * Get all tiles, grouped by category.
      */
     List<DashboardCategory> getAllCategories();
+
+    /**
+     * Returns a priority group for tile. priority level is grouped into hundreds. tiles with
+     * priority 100 - 199 belongs to priority level 100, tiles with priority 200 - 299 is in
+     * group 200, and so on.
+     */
+    int getPriorityGroup(Tile tile);
 }