legacy full style item is introduced Efl.Ui.ListEmptyItem Class in new Efl Interface,
but using "Empty" name is too ambiguous to present style usage.
Thanks to @cedric and @segfaultxavi,
I found better name for this class, Efl.Ui.ListPlaceHolderItem,
as item hold the place which need to be replaced and relayouted by user generated content.
Depends on D8582