Improve RESTfulness for collection URIs

[cnrdh]

We need a robust mechanism to GET all documents in a collection.

The API co-evolved from ideas similar to those expressed in http://tools.ietf.org/html/draft-kelly-json-hal-06 - with widespread use of hyperlinks between documents. However, at the collection level, we lack links from the Collection URI to bundles of documents (similar to a database view). With such links, RESTful clients could follow a simple set of rules to download entire collections

[cnrdh]

We now have HAL support for ES queries, but not for endpoints.

We could start by redirecting from /endpoint to /endpoint/?q=&format=hal