Support flexible DataCite resourceType metadata in a Dataset

tl;dr: Dataverse should offer a UI component to select the general dataset type with a CV based on DataCite/Dublin Core. The selected type should be used for metadata registration at DataCite.

Related issues:

• #2917 (this new issue is only about a part of what is mentioned there)
• #5086 (which is about doing the same but for file level DOIs)

Jülich DATA has an open request by @sciapp to publish software in our repo and get a DOI for releases (so inline with FORCE11 recommendations and DataCite recommendations).

Recently, the RDA WG has published a paper open for community comments about the different PID options for software publications. The interesting part for Dataverse is the diagram for registered software datasets at Datacite.

Currently, software that gets published via Dataverse, will have a resourceTypeGeneral="DataSet" attached to it, as the metadata template does not allow for customization. (This is also true for #5086, where we might think about using type "Collection" for the dataset automatically and specific types for the files.)

Having software counted as "DataSet" makes things less discoverable and does not push research software engineering forward. See DataCite Schema Docs for a complete list of types.

A full example of software metadata can be found at DataCite.

Things to do for an implementation:

1. Obviously, this will need a new metadata field in citation.tsv, using a controlled vocabulary based on resourceTypeGeneral. Should be mandatory, but happy to discuss. This will definitely have to be present onCreate, but could use "DataSet" as a default!
2. Extend the metadata template and code to fill in the value selected in UI.
3. Extend the metadata exporters where feasible.

As this is a request to our ZB services and will become more important for Software Citations, we offer implementing it at the dataset level. Maybe @philippconzett can collaborate to provide it for file level in the same go?
Comments please! 🚀

Pinging @IngoHeimbach @doigl @bronger @mfenner @TaniaSchlatter

Start with src/main/resources/edu/harvard/iq/dataverse/datacite_metadata_template.xml and the citation.tsv metadata definition, then trace the code that fills the DataCite template and the metadata exporters. Done means a dataset-level UI value using the DataCite resourceTypeGeneral vocabulary is stored, applied during registration, and exported where feasible, with the existing DataSet default behavior addressed.