registered-urns: new adp-include for listing registered URNs
This function is useful e.g. for the packages using optionally CDN or local resources. It helps an admin for testing the registered resources (e.g. via sitewide-admin pages).
provided a helper proc to query the mapping of a generic icon name to a concrete
This function is necessary in boundary cases, where e.g. a display_template passes the generic name of the icon via template variables which have to be @-substituted before adp-tag resolution, which performs the regular icon name mapping (otherwise, the tag resolver receives e.g. ...name=@icon@...)