cubicweb-skos #5689852 Use new CW 3.21 dataimport API. [validation pending]

This will purge lot of things that have nothing to do with SKOS,

prioritynormal
typeenhancement
done in0.8.0
load left0.000
closed by#7b861a9c0a8b [dataimport] Conform to the new CW 3.21 dataimport API
patch[dataimport] Conform to the new CW 3.21 dataimport API [applied][dataimport] Conforms to the new CW 3.21 dataimport API. [folded]