Initial screens for Storage Access.

This new settings will be accessed through Apps -> Special Apps and it will let
users change the status of granted (or denied) Scoped Access Permissions.

This initial CL implements the landing activity that shows all packages and an
initial version of the detailed activity for a specific page, althouth the
detailed activity is not ready yet.

Test: manual verification
Test: export ROBOTEST_FILTER=com.android.settings.core.codeinspection.CodeInspectionTest && make RunSettingsRoboTests -j40
Bug: 63720392

Change-Id: Id0419c2c4aaaec365803218d6947e230e4776f13

src/com/android/settings/Settings.java

@@ -120,6 +120,7 @@ public class Settings extends SettingsActivity {
     public static class PhotosStorageActivity extends SettingsActivity {
         /* empty */
     }
+    public static class StorageAccessSettingsActivity extends SettingsActivity { /* empty */ }
 
     public static class TopLevelSettings extends SettingsActivity { /* empty */ }
     public static class ApnSettingsActivity extends SettingsActivity { /* empty */ }