[Feature Request] KaaS: Concrete method to verify that control planes are on different physical hosts

There are various ways of handling control planes on the different Kubernetes platforms. Some platforms have the control planes virtualized in one / multiple shared clusters, others have them on physical machines.

We have written down in the standard that the control planes MUST be on different physical hosts.

As there is no way of testing this programmatically, we need to find a way of handling this aspect in a certification process.

I propose that we let the provider write down the measures that are taken to fulfill this requirement.

A short summary, e.g. for a Gardener instance on OpenStack, would show that the provider took the required measures.