What is the correct predicate to use for a PROF Profile's preferred token?

[ashleysommer]

@nicholascar I need your expert determination on this.

PROF ontology has a property called hasToken to identify a Profile's preferred token to use.
But all of the Prez built-in Profiles use dcterms:identifier (with xsd:token data-type) for their token.

prez/prez/reference_data/profiles/vocprez_default_profiles.ttl

Lines 18 to 21 in 45e8426

	prez:VocPrezProfile
	a prof:Profile ;
	prez:supportedSearchMethod prez:exactMatch , prez:skosPrefLabel , prez:skosWeighted , prez:jenaFTName ;
	dcterms:identifier "vocprez"^^xsd:token ;

I think the latter (dcterms:identifier with token data-type) fits better with the more recent thinking around "fewer custom properties in ontologies" and "use data-types where appropriate for string identifiers", but we should probably also support the actual PROF ontology standard of hasToken too.

[ashleysommer]

Related to w3c/dxwg#453 and w3c/dxwg#1061
Both of those threads are talking about this, but neither suggest the use of dcterms:identifier so I don't know where that has come from.