Ogm 521 natural one to one

https://hibernate.atlassian.net/browse/OGM-521

This patch will remove the redundant column created for *ToOne associations on nodes.
I add to add some metadata in the TupleContext to achieve this.
> "The association from Husband to Wife will be mapped as a relationship in Neo4j. If required, the id of the associated Wife entity can be obtained by navigating to the related Wife node and reading its id."

Sounds a lot better, I'll replace it