Use Cases to support Download Terms of Use and Guestbook

[ChengShi-1]

Depends on IQSS/dataverse#12110

To support production file download in the SPA, we need to add a form for the user to accept terms of use & sign the guestbook, if required (replicating JSF UI).

In Get Dataset endpoint, update the response to also return the Guestbook for the dataset, if it exists.
Update download API endpoint: Save Guestbook Response - saves the guestbook data entered by the user at time of download.