[Spike - API] Extend the Files API to retrieve file counts by type, access and category

[GPortas]

Overview of the Feature Request

We need this API extension to support dataset files tab display data in the new frontend, since the file counts by type, access, and category, are required by the different tab filters and pagination info.

What kind of user is the feature intended for?

API User

What inspired the request?

• Integrating features in the SPA ([Spike - Integration] [1/2] Create the File Tab of the Dataset page - Display data dataverse-frontend#134)
• Performance: Slow response for the versions API call with large number of files or versions #9763 (comment)

What existing behavior do you want changed?

None

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

New API endpoint to retrieve file counts by type

Any open or closed issues related to this feature request?

• [Spike - Integration] [1/2] Create the File Tab of the Dataset page - Display data dataverse-frontend#134