add new media type "application/rdf+xml"

In Bibliothek der Neologie, all RDF/XML Objects are rewritten to be of media type "application/rdf+xml" instead of "text/tg.inputform+rdf+xml" because they are no longer of the type of the latter, and tg-forms is no longer used in TextgridLab, for which this custom media type was used to have resources of this kind opened with it.

What do I exspect? The media type "application/rdf+xml" is added to all layers of repository functionality, including search and UI. It could replace the "text/tg.inputform+rdf+xml" media type or be introduced additionally.