Handle missing copy function for configurations

We currently don't have a copy function for configurations in the frontend. But we have the entry in the context menu. So we must discuss on how we want to implement it.

Background is that the configuration contains mostly of actions for very specific devices. Copying the tree with exaclty this platforms and devices should not even be allowed - as this would mean that the very same device (the same physical thing) would be in multiple configurations at the same time.

So we need another idea - or make the decision that we don't want to allow copies of configurations at all.