Add support for previewing a IIIF image reference

[thatbudakguy]

This is for an image reference (info.json URL only), not manifest. In this case, we won't ever be able to render a map, because there won't be a georeference annotation tied to the image. We can use OpenSeaDragon for the zoomable image.

If we have a bounding box (dcat_bbox) or geometry (locn_geometry), it might be nice to render a small non-interactive static inset map, kind of in the same way that geoblacklight does (image from BTAA geoportal):