Document that the whole class hierarchy of a service implementation must be available in Jandex

[ppalaga]

Follows up #1427

The new page should go under https://docs.quarkiverse.io/quarkus-cxf/dev/user-guide/advanced-service-topics.html

The text can be partly taken from https://docs.quarkiverse.io/quarkus-cxf/dev/release-notes/3.13.0.html#_1427_better_exception_message_when_a_service_interface_is_not_available_in_jandex