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/Settings.java

@@ -68,7 +68,10 @@ public class Settings extends SettingsActivity {
     }
     public static class BackgroundCheckSummaryActivity extends SettingsActivity { /* empty */ }
     public static class StorageUseActivity extends SettingsActivity { /* empty */ }
-    public static class DevelopmentSettingsActivity extends SettingsActivity { /* empty */ }
+    public static class DevelopmentSettingsActivity extends SettingsActivity {
+        public static final String DASHBOARD_ALIAS =
+                "com.android.settings.DevelopmentSettingsDashboardAlias";
+    }
     public static class AccessibilitySettingsActivity extends SettingsActivity { /* empty */ }
     public static class CaptioningSettingsActivity extends SettingsActivity { /* empty */ }
     public static class AccessibilityInversionSettingsActivity extends SettingsActivity { /* empty */ }
@@ -161,6 +164,7 @@ public class Settings extends SettingsActivity {
     public static class SystemSettings extends SettingsActivity { /* empty */ }
 
     // Top level categories for new IA
-    public static class SupportActivity extends SettingsActivity {}
+    public static class SystemDashboardActivity extends SettingsActivity {}
+    public static class SupportDashboardActivity extends SettingsActivity {}
 
 }