Fork a new developer options page.

- Create a new activity/fragment and add it to manifest
- Mark old activity/fragment deprecated
- Enable/disable the new activity based on FeatureFlag
- Initial skeleton code for new fragment

Bug: 65522852
Test: make RunSettingsRoboTests -j40 ROBOTEST_FILTER=DevelopmentSettingsDashboardFragmentTest
Change-Id: Ib1395693f8b6f61d4726573a9ea841ea53cf207b

src/com/android/settings/core/gateway/SettingsGateway.java

@@ -66,6 +66,7 @@ import com.android.settings.datausage.DataUsageList;
 import com.android.settings.datausage.DataUsageSummary;
 import com.android.settings.deletionhelper.AutomaticStorageManagerSettings;
 import com.android.settings.development.DevelopmentSettings;
+import com.android.settings.development.DevelopmentSettingsDashboardFragment;
 import com.android.settings.deviceinfo.ImeiInformation;
 import com.android.settings.deviceinfo.PrivateVolumeForget;
 import com.android.settings.deviceinfo.PrivateVolumeSettings;
@@ -177,6 +178,7 @@ public class SettingsGateway {
             PrivateVolumeSettings.class.getName(),
             PublicVolumeSettings.class.getName(),
             DevelopmentSettings.class.getName(),
+            DevelopmentSettingsDashboardFragment.class.getName(),
             AndroidBeam.class.getName(),
             WifiDisplaySettings.class.getName(),
             PowerUsageSummary.class.getName(),