Portlet: save page layout in an instance

[Clara-Exoplatform]

Is your feature request related to a problem? Please describe.
I'm always frustrated when I want to use an portlet instance but there is not layout.

Describe the solution you'd like
I would like to save first the content of the portlet and then the layout. At the end, save both in one and only instance of a portlet.

Additional context
Exemple : In a client DW, I use the portlet image with a margin, a fix height in every menu of the platform. Today, I can't save these parameters within the instance.