Add sample application that demonstrates how to create an entity and its association with another entity in a single HTTP call

[ruthst00]

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Description

This example project shows how to create an entity and its association with another entity in a single HTTP call.

For example, given parent entity "Parent" and child entity "Child" that is associated with a given Parent, you can create new parent and associated child records with a single HTTP call.

This example project and its documentation attempts to solve DATAREST-1036

[ruthst00]

Hi, can someone help me with instructions for resolving this failing check? It looks like it might be a build failure that's out of my control:
https://github.com/spring-projects/spring-data-examples/actions/runs/32461885783/job/96710289079?pr=715

Thanks in advance