feat: [SubPR] Implement GQL Datamodels

Created by: Tirokk

Pullrequest

Implement GQL datamodels.

Issues

• relates #4701
• relates #4548 (closed)

Todo

I decided to do the following later if there’s a use case and do KISS:

• set a relation to one :Profile node on all profiles?
  • then Cypher can look like this: MATCH (profile)-[:BELONGS-TO]->(:Profile) RETURN profile {.*}