elm_focus: implement missing functions

elm_focus: implement missing functions

there is one function that needs to be implemented by the inheritor of
Efl.Ui.Focus.Object and that is focus_parent, otherwise child_focus
cannot be propagated correctly. This is now achived correctly for all
widgets.

This fixes from elm_object_focus_get results for toolbar and calendar.
Segmentcontrol inherits from the class, however, the widget itself does
not allow focus, so its never registered probebly.

Differential Revision: https://phab.enlightenment.org/D7331