cubicweb-datacat #8357660 add an action to export a catalog in RDF [validation pending]

as for datasets

prioritynormal
typeenhancement
done in0.5.0
load0.500
load left0.000
closed by#cf8570bbbb16 [views] Add an action to export datasets of a catalog in RDF
patch[views] Add an action to export datasets of a catalog in RDF [applied]