[GEP-28] Extend CreateMachineResult to include InternalIP

[jamand]

How to categorize this issue?

/area ipcei
/kind enhancement

What would you like to be added:

gardener/machine-controller-manager#1007 added Hostname to the new Machine status.addresses field. As some cloud providers may not resolve this hostname, it is necessary to add internal IP addresses to resolve.

Why is this needed:

See gardener/machine-controller-manager#1007 and linked issues/docs.