website_formio: Update source (on page) to apply the iFrameResizer bodyMargin (property)

[bobslee]

Problem

After a form has been dropped on a website page, its properties can't be updated.
Currently the iFrameResizer its bodyMargin property needs such update, when this has been updated in the Form Builder.

Improvement (feature request)

Result:
Update the source (on the page) to apply the iFrameResizer bodyMargin (property).

Implementation suggestion:
When in "website editor modue", add a button/link (eg form onhover) or a sidebar property to update this bodyMargin setting.