Support for spring-data 4.0.0

[jcalcote]

I'm just posting this issue here as a placeholder for the work required to make cosium work with spring data 4.0.0

[aausting]

I implemented support for spring-data-jpa 4.0.0.RC2. But it needs some polishing.

See: master...aausting:spring-data-jpa-entity-graph:feature/spring-data-4

Tests are fine. But generator is not working yet.