ch-core-document: add check that fullUrl exists and is an absolute url

[oliveregger]

a constraint should be added that to satisfy the requirements when the fullUrl is specified in a document bundle:
URI for resource (Absolute URL server address or URI for UUID/OID)

Except for transactions and batches, each entry in a Bundle must have a fullUrl which is the identity of the resource in the entry. Note that this is not a versioned reference to the resource, but its identity. Where a resource is not assigned a persistent identity that can be used in the Bundle, a UUID should be used (urn:uuid:...).

see also related issue from projecathon: https://gazelle.ihe.net/jira/browse/EHS-443