support for agents in dcterms:contributor

[pwoltjer]

The use of Agents in dcterms:contributor does not seem to work.

It would be nice if Agents in dctermst:contributor would be allowed, just as with dcterms:creator. So this would be rendered nicely:

dcterms:creator   [ a                        sdo:Person ;
                                  sdo:name        "Pieter Woltjer" ;
                                  sdo:affiliation [ sdo:name "CBG|Center for familiy history"@en ;
                                                              sdo:url  "https://cbg.nl" ] ;
                                  sdo:email        "[email protected]" ] ;