[CCUT] add prefixes and namespaces in response (return graph/triples)

[basels]

Namespaces and prefixes should be returned as part of the response to the following APIs:

/get_canonical_json
/trans_form

The return response should be a graph/triples (in ttl and/or json-ld format) and should include the following in its header:

@prefix qudtp: <http://www.qudt.org/qudt/owl/1.0.0/qudt/Properties.html#> .
@prefix qudtu: <http://www.qudt.org/qudt/owl/1.0.0/unit/Instances.html#> .
@prefix qudt:  <http://www.qudt.org/qudt/owl/1.0.0/qudt/#> .
@prefix ccut:  <https://w3id.org/mint/ccut#> .

Originated in this issue.