CreationTime not returned from Download/Find APIs

[MarkusHorstmann]

The specification calls for a CreationTime field in UANodeResults that reflects the time the namespace was created, presumably when it was uploaded to the cloud library. It is distinct from the PublicationDate.
In the current implementation we renamed the CreationTime to PublicationDate and some of the records in the database reflect that correctly while others return the upload time.

Proposal:

1. Add the CreationField back
2. Store and return the PublicationDate/NamespaceUri as part of the metadata. Update the specification accordingly.
   OR remove the Version field from the UANamespaceResult and return PublicationDate/NamespaceUri/Version only with the NodeSet/NodeSet2 datastructure.
3. Clean up existing database records to be consistent.

Additional proposal (implementation only):
4. Store the predefined metadata as a well-defined database table instead of in the name-value-pair table. Leave the name-value-pair table only for additional/custom properties.