Remove request deduplication (scionproto#2730)

It is hard to follow requests with the deduplication enabled
(debug id gets lost and it's not clear how to map multiple debug ids to a single dedupe context.)
Furthermore there is no clear evidence that we even save any time in a current real world deployment of scion.
Once we have clear evidence that deduplication needs to be at a certain location we can always readd it, but then we can do a more informed decision where it is actually needed.