extend publicationReference category ?

[lzehl]

currently the "publicationReference" category is composed of:

• "core:DOI",
• "core:HANDLE",
• "core:ISBN",
• "core:ISSN",
• "publications:Book",
• "publications:Chapter",
• "publications:ScholarlyArticle"

However I think we should include here all digital identifier for digital resources:

• RRID (in case of atlases for example)
• IdentifiersDotOrgID (in case of data for example)
• SWHID (not sure about that one?)
• GenericIdentifier (in case of ID types we don't have yet)

@apdavison what would be your feedback here?