Prefer handle based copy workflow within translationworkflow

The TranslationWorkflow uses a nested copy workflow (category "translation-copy") to copy documents and assets.
With the new DocumentWorkflow, which is configured on the handle, this should be preferred to the now deprecated FullReviewedActionsWorkflow.
However for assets still the DefaultWorkflow is/needs to be used which is configured on the document itself.
The TranslationWorkflow(Impl) therefore should first try to find a matching copy workflow defined on the handle, but use as fallback the lookup on the document itself, as before.