Add section on recommended server documentation

[nichtich]

A DAIA server SHOULD be publicly available and documented with information such as

• which kind of request identifiers are supported
• a list of expected service type URIs
• a list of expected institution, department, and storage URIs
• a list of expected limitation type URIs
• supported languages

The lists could be provided as part of a DAIA response if and only if no query parameter id is given:

{
  "document": [ ],
  "entities": {
    "institutions": [ ... ],
    "departments": [ ... ],
    "storages": [ ...],
    "services": [ ... ],
    "limitations": [ ... ],
  }
}

each entry as entity with mandatory id.

• whether and how patron-specific availability is supported (a list of patron types)
• which database that identifiers come from

[nichtich]

The server could also show what kind of identifiers it expects (e.g. publish a URI prefix)

[nichtich]

Such doument could be referenced with a HTTP Link header.

[nichtich]

The server documentation could be a JSON Hyper-Schema document or similar with Link Description Objects (LDO) that link to the actual entities

{
    "storages": [{
      "href": "/storages",
      "rel": "related"
    }]
}

However, as I understand JSON Hyperschema, the "links" element should be part of JSON Schema so it is not applicable here (?)