Paging for GET /api/resource

[kba]

Since there can be resources in the range of millions, it's unfeasible to return every resource in a collection on a GET call to the resource.

This is what caused #71 and was fixed ad-hoc by infolis/mongoose-jsonld@3d70378.

Implementing this is simple, just need to make sure not to miss anything:

• Define number of results (documents, not triples) per collection in schema.tson, default to 100 (or something)
• Add page to GET /api/{modelName} Swagger docs
• Add page to GET /api/{modelName} RESTful call, default to 0
• Add some form of hypermedia control to the HTTP Response (probably Link in some form, need to investigate)
• Define the default sorting behavior in such a way that this is stable (per default: oldest to newest?)