Searches can return IIIF Collection manifests

[cjcolvar]

Proof of concept

Test by making a search and then adding /manifest.json to the url after /catalog and before the query params.

TODO: Implement paging by including a final item that is the same url as the manifest but with the page query param advanced. See Northwestern's implementation of collection manifests.
E.g. https://dc.library.northwestern.edu/collections/d3a8e587-cc58-4cb0-aea2-65465d42ec3e

{
      "id": "https://api.dc.library.northwestern.edu/api/v2/collections/d3a8e587-cc58-4cb0-aea2-65465d42ec3e?as=iiif&page=2",
      "type": "Collection",
      "label": {
        "none": [
          "Next page"
        ]
      }
    }