Dataset types should have a display name

[pdurbin]

Currently dataset types have an id and a name.

As discussed during standup today, there should also be a display name.

We came to this conclusion in the context of https://github.com/IQSS/dataverse-frontend/pull/845 where I'm adding a entry like "newReview": "New Review", in a file for English strings but this won't work because superusers can add whatever types they want.

From https://guides.dataverse.org/en/6.8/schemaspy/tables/datasettype.html