Extend uuid invariant #6
Description
Extend the invariant 'uuid': https://medcomfhir.dk/ig/document/StructureDefinition-medcom-documentreference.html#constraints, so it allows the uuid to be prefixed with 'urn:uuid:', to ease implementation on NSP:
value.matches('[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}' or 'urn:uuid:[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}')