Updating dcat3-external.*

[riccardoAlbertoni]

Attempt to address #1498. Closes #1498

• [X] to turn dcterm into dcterms;
• [X] to update the definitions (skos:definition) as listed in #1498;
• [X] to add spdx terms and class;
• [x] ?? to decide if we need to update all the "in the context of DCAT 2" to "in the context of DCAT 3" for DCAT 2 Legacy properties
• [x] ?? to decide if we want to add "skos:changeNote "Property added in this context in DCAT 3.0."@en ;" for new properties;
• [x] ?? to check if phrasings of usage notes have changed in the meanwhile in the document. In case of conflict, we replace with the one from the document;
• [x] to update the usage note as listed in #1498;
• [x] to add skos:editorialNote to warn that translations needs to be updated.
• [x] to update the related json-ld and rdf/xml serializations.

[riccardoAlbertoni]

Should we turn all the occurences of "in the context of DCAT 2" inseted in the skos:scopeNotes to "in the context of DCAT 3"? Or do we prefer to update only the skos:scopeNotes that have changed by DCAT 3?

If you think that keeping track of when a property has been added is advisable, please consider that independently from the decision on skos:scopeNotes, the history is registered anyway, as we have used skos:changeNote to specify whether the property/class was adopted in DCAT 2 or 3.

[riccardoAlbertoni]

After discussion in DCAT subgroup https://www.w3.org/2022/11/03-dxwgdcat-minutes, we agreed:

• For all the terms introduced in DCAT 2, we can keep the existing skos:changeNote "Property added in this context in DCAT 2.0."@en ; to track when each term has been included.
• For new terms in DCAT 3, we can add skos:changeNote "Property added in this context in DCAT 3.0."@en ;
• For DCAT 2 Legacy terms, we can update skos:scopeNote and skos:definition by turning “in the context of DCAT 2" to "in the context of DCAT" , we update the existing notes/definition with the novel versions.
• we only provide the reference to the original document when definitions of borrowed terms are consistent with the original, for example, [SPDX] in skos:definition "The checksumValue property provides a lowercase hexadecimal encoded digest value produced using a specific algorithm [SPDX]."@en

[riccardoAlbertoni]

I have completed the work required on the turtle for external terms. Updated DCAT mentions and implemented the changes required by Andrea. I think this is ready for merge, so I ask the co-editors to review the PR, and if they do not find issues, we can merge this PR.