Make custom SessionSerializationCallback usable with the Kubernetes Kit Debugger

[MichaelPluessErni]

As mentioned in the comments of this task: #113

The SessionSerializationCallback cannot be used with the Kubernetes Kit Debugger, because the DEFAULT SessionSerializationCallback is hardcoded in SerializationDebugRequestHandler::serializeAndDeserialize.

It would be cool, if it was possible to inject a custom callback bean when testing an application with the Kubernetes Kit Debug Tool.

It could make sense for the callback injected into SerializationDebugRequestHandler to have a specific qualifier so that it might be different from the callback used in production.