add persistableRelationship and adjust Neo4j

[mshima]

Neo4j fetches and persists the entire graph.

• add warn about DTO incompatibility.
• add warn about User relationship security (User will be persisted).
• every relationship is editable.
• use @JsonIdentityInfo instead of @JsonIgnore.

Fixes #24076
Fixes #13797

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[DanielFran]

Did not validate all apps, seems OK

[mshima]

The daily builds error is not reproducible using jhipster generate-sample daily-react-maven-neo4j. 😕