Disable temporarily result layout configuration when content view is flagged "DAM"

The default DAM content view needs a box-like result layout.

Waiting for this to be configurable in Studio, disable the editor for result layouts, and at build time, use the default DAM result layout.

(The result will still have some configurability since by default it displays a form layout: this one can be overriden)

+ display a validation error when user selects more flags associated with the "DAM" one.