Feature Request: Add option to create/export/import personal dataset templates

Overview of the Feature Request
Introduce support for personal templates in Dataverse, allowing users to create and reuse dataset templates tied to their account rather than to a specific collection. This would improve usability for curators and depositors who manage datasets across multiple collections.

Additionally, explore the ability to export and import templates as jsons. This way you can also share a personal template with one other person or provide a set of starter templates somewhere for users to get started with. E.g. a specific json can be shared in a research group that includes the metadata all researchers should use in that group or for all datasets related to a specific project.

What kind of user is the feature intended for?

Depositor

What inspired the request?
Conversations at KU Leuven on how we currently don't really use templates in an institutional set-up as its scope is too broad/general. However we do have departments that have a single person responsible for dataset creation. These users would benefit from having personal templates to streamline their workflow, also when working across different collections.

What existing behavior do you want changed?
Currently, templates are tied to collections. This limits their usability for users who manage datasets across multiple collections or who want to reuse their own templates regardless of collection context.

Any brand new behavior do you want to add to Dataverse?

• Allow users to create and manage personal templates tied to their account.
• Enable the use of personal templates when creating datasets in any collection.
• Possibly allow sharing of personal templates across teams or institutions (possibly through the json export/import idea).

Any open or closed issues related to this feature request?
Not explicitly linked yet, but related to ongoing discussions around dataset templates and usability improvements in relation to templates in the SPA

Are you thinking about creating a pull request for this feature?
It could perhaps be possible to pick up in the SPA implementation of templates? We're not planning on picking this feature request up ourselves at the moment.

Start by reviewing the existing collection-scoped template behavior and the SPA implementation of templates, both referenced in the request. Define the scope for personal template creation, management, use across collections, and JSON export/import; the work is done when those flows and their sharing expectations are specified and covered.