Revert merge made while half asleep.

Revert "Merge branch 'TP-2.3.0' of github.com:mikesname/neo4j-ehri-plugin"

This reverts commit 28632aaccb7a05e25cc7c81dd474dc8df1db673f, reversing
changes made to 6e8b2eb024dbb33bae7ccd3c5f000d17051867b4.
Cleanup of models, prior to larger refactoring
Cleanup of models, prior to larger refactoring
Cleanup of models, prior to larger refactoring