Generate IIIF collection URI's for image collections

[snydman]

We should generate collection level IIIF URI's for our defined image collections, following the spec:

http://iiif.io/api/presentation/2.1/#collection

A top level collection manifest of collections would be good too.

[aeschylus]

Here is an example from Jeff Witt's project: http://scta.info/iiif/collection/scta

Some other quasi-collections: http://iiif.archivelab.org/iiif/collection.json

[aeschylus]

Context: https://groups.google.com/forum/#!topic/iiif-discuss/r1ANaZG-BQo

[cbeer]

I'm not sure we currently publish enough information to PURL for it to a) identify an image collection, and b) build a collection manifest that lists the members of that collection.