Add terms of use and guestbook to file download

[ekraffmiller]

When a dataset has terms of use or a guestbook defined, the UI should show the terms of use and guestbook for the user to accept and fill out before continuing with the download.

Download Terms of Use example, with Guestbook form:

Depends on API updates to get the Guestbook and store the guestbook response: IQSS/dataverse#12001