efl_ui/image: add group_calc implementation, use deferred calc for sizing

efl_ui/image: add group_calc implementation, use deferred calc for sizing

this changes image internals to use the more standardized group_calc method
of sizing and causes all previous operations on the image which would have
resulted in an immediate recalc to instead defer the calc until the
group_calc function is called

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D9686