Adding an information about the fact that a data is available with authorization

[IGNF-Xavier]

In certain circumstances, it is possible that a service (WMS, WMTS, WFS or download) is only available with restricted access.
But for the end-user, it is always interesting to know that a data exists and eventually contact the owner to acces it.

In this case, the map visualization on the data page is not available and displays the message "the service is not available".
Can we add a new message which displays that the service is under restricted access?