cubicweb-relationwidget #10929815 Creation from buttons [in-progress]

In order to avoid confusion between dialog buttons and creation form buttons , display the creation from buttons on the rigth of the form.

prioritynormal
typebug
done in0.5.0
load0.200
load left0.200
closed by<not specified>
patch[creation form] display the button group on the right of the form [in-progress]