select keyword from thesaurus

[pvgenuchten]

in stead of typing out a thesaurus and a keyword, introduce a mechanism which presents a selection option for keywords of a thesaurus.

Initially we could store the thesaurus as json in codelists, but alternative is to load the thesaurus from a skos repository using sparql or directly as json-ld/ttl

for example: https://github.com/rapw3k/glosis/blob/master/glosis_cl.ttl