context should define more props as @id

[VladimirAlexiev]

The JSONLD context https://w3id.org/dspace/2024/1/context.json should define these props as @type: @id:
dcat:dataset, dcat:servesDataset, dcat:service, dcat:accessService, odrl:hasPolicy, odrl:permission, odrl:prohibition, odrl:obligation, odrl:duty, odrl:constraint, odrl:profile
(and there is no need to specify @container: @set" because that's default).

Otherwise there are problems eg with this EDC/Sovity response:

{
    "@id": "bcca61be-e82e-4da6-bfec-9716a56cef35",
    "@type": "dcat:Dataset",
    "dcat:distribution": [
      {
        "@type": "dcat:Distribution",
        "dcat:accessService": "5e839777-d93e-4785-8972-1005f51cf367"
      }
    ]
  },
  "dcat:service": {
    "@id": "5e839777-d93e-4785-8972-1005f51cf367",
    "@type": "dcat:DataService",
  },

When converted to Turtle, you can see a disconnected graph since accessService is left as a string:

<file:///D:/Onto/proj/underpin/model/dcat/bcca61be-e82e-4da6-bfec-9716a56cef35>
        a                  dcat:Dataset;
        dcat:distribution  [ a                   dcat:Distribution;
                             dcat:accessService  "5e839777-d93e-4785-8972-1005f51cf367"
                           ] .

<file:///D:/Onto/proj/underpin/model/dcat/5e839777-d93e-4785-8972-1005f51cf367>
        a                dcat:DataService.

(Note: the local-folder URLs is another problem, as described in sovity/edc-ce#1077)