Address technical debt following integration of Hibernate Reactive 2.0.0.Alpha2

[Sanne]

Description

For sake of iterarive development and re-enabling CI monitoring on the Hibernate Reactive modules, we're merging pr #31454 with some pending tasks still open:

• Need to investigate test which was disabled in f6584a19443d22b1289d686b29c7dd205323d4c9 ( See comments in extensions/panache/hibernate-reactive-rest-data-panache/deployment/src/test/java/io/quarkus/hibernate/reactive/rest/data/panache/deployment/openapi/OpenApiIntegrationTest.java)
• @yrodiere applied some improvements on the Hibernate ORM (blocking) extension to enhanced the Dialect selection, in particular configured versions. We might want to follow up and align the HR extension to this.
• Ideally not ship with an Alpha release? Or flag the extension appropriately as early preview.
• Migration guide work?

Implementation ideas

No response

[quarkus-bot[bot]]

/cc @DavideD (hibernate-reactive), @gavinking (hibernate-reactive)

[yrodiere]

Looks like https://github.com/quarkusio/quarkus/pull/31947 (configurable default optimizer, defaulting to pooled-lo) would need to be ported to Reactive as well

[yrodiere]

Looks like #31947 (configurable default optimizer, defaulting to pooled-lo) would need to be ported to Reactive as well

This particular issue is being addressed in #32044, but the rest isn't.

[Sanne]

Adding: we should add the integration tests provided in https://github.com/quarkusio/quarkus/issues/32040#issuecomment-1480803506