[Spike - API] Create an endpoint to retrieve dataset thumbnails

Overview of the Feature Request

The SPA needs to obtain the thumbnail for a particular dataset to display it on the page.

Thumbnails come from different sources, such as an uploaded file or a specific image uploaded by the user, and their accessibility depends on the user permissions.

The origin of the thumbnail, or the permissions, should not be an issue for the SPA, since the new endpoint should return the thumbnail regardless of the origin and considering the calling user's permissions. Potentially the endpoint will function similarly to the access endpoint for downloading file thumbnails.

What kind of user is the feature intended for?

API User

What inspired the request?

SPA needs

What existing behavior do you want changed?

None

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

New API endpoint for retrieving dataset thumbnails

Any open or closed issues related to this feature request?

• https://github.com/IQSS/dataverse-frontend/pull/202

Start by reviewing the existing access endpoint for downloading file thumbnails and the related dataverse-frontend pull request 202. Trace the API entry points and determine how thumbnail origins and calling-user permissions are handled. Done means a documented endpoint returns the appropriate dataset thumbnail regardless of its source, subject to permissions.