[ABS] Set proper elementary parent to elm_layout

[ABS] Set proper elementary parent to elm_layout

Summary:
In the past, elm_layout's parent was elm_box. But this idea
was wrong because the box widget was contained to the layout
widget. That made recursive parent referencing between two
widgets.
So, I've chagned the parent of elm_layout to the naviframe widget.

Reference: submit/tizen/20200205.123246
Commit id: d24edc719fe402a2b31417c0b0b9115170d83f0a
Requested by: a.pandia1@samsung.com
SDK rootstrap version: 20200205_2