Dependency fixes for Hibernate extensions

[yrodiere]

The first item will likely require that we open an issue, because critically, it means Quarkus users can't rely on the BOM to apply, since the BOM doesn't manage Maven's <annotationProcessorPaths> and hibernate-orm.version doesn't get propagated to POMs using our BOM.

Not sure about changes in the second commit, but let's CI what CI has to say.

1. Properly apply annotation processors in Panache-Hibernate extensions

   Unfortunately, HHH-17362 doesn't fix the problem,
   and it's unlikely that it will ever be fixed.
   See https://hibernate.atlassian.net/browse/HHH-17362?focusedCommentId=113465

   We'll have to apply annotation processors the "right" way, as explained
   in https://github.com/hibernate/hibernate-orm/blob/6.3/migration-guide.adoc

2. Fix some wonky dependency exclusions in Hibernate ORM/Reactive/Search extensions

   1. It makes no sense to exclude a transitive dependency if its version
      is managed and we re-declare that dependency ourselves two lines
      below.
   2. jakarta.xml.bind-api and jakarta.activation-api are not banned at
      all, are actually transitive dependencies of hibernate-core and
      hibernate-jpamodelgen, and have their version managed in our BOM.
      So there's no need to exclude these transitive dependencies
      or to declare them when we don't use them directly.
   3. jakarta.activation-api is a dependency of jakarta.xml.bind-api,
      so there's no point excluding jakarta.activation-api if the same
      module is going to depend on jakarta.xml.bind-api.
   4. org.jboss:jandex (old artifact) is no longer a dependency of Hibernate ORM,
      so we don't need to exclude it.
   5. io.smallrye:jandex (new artifact) is never required as a runtime dependency
      of Hibernate ORM, so it should be excluded directly in the BOM.

[quarkus-bot]

/cc @Sanne (hibernate-orm), @gsmet (hibernate-orm,hibernate-search)

[quarkus-bot]

✔️ The latest workflow run for the pull request has completed successfully.

It should be safe to merge provided you have a look at the other checks in the summary.

[gsmet]

Yeah these were leftovers of when we weren't using these artifacts.