+ Rdf namespaces are queried from database (not to rely on defined namespaces in rdf file) to solve the bug
+ Another bug (which overwrites existing vocabulary concept element values) is resolved. Now all seen predicates are appended if object value does not already exist.
+ Unit tests are updated to conform changes
+ Wording & Code formatting updates
Refs: #19963
Merge branch 'master' of https://github.com/eea/eionet.datadict