Add integration tests for other Java EE / Jakarta EE servers

[jpraet]

The EE integration for rest-problem-java is currently only used and tested on JBoss EAP.

We should add integration tests for some other Java EE / Jakarta EE servers too.

But we better focus on those application servers that are actually used by the institutions that implement the Belgif guidelines.

@pvdbosch are any other java application servers used at Smals?
@VirginieHayot and at eHealth?
@barthanssens and at BOSA?
others?

[pvdbosch]

We're not using any other app servers currently for significant new application development.