In 4.15 Kuryr is no longer a supported NetworkType, following its
deprecation in 4.12. This commit removes mentions of Kuryr from the
documentation and code, but also adds validation to prevent
installations from being executed when `networkType` is set to `Kuryr`.
The `MachinesSubnet` field has been reshaped as `controlPlanePort`,
this commit updates the docs to ensure `controlPlanePort` is used.
Also, this commit adds dual-stack documentation.
OpenShift 4.6 does not support adding a MachineSet on a separate subnet.
Removing the corresponding use case from the baremetal-workers
documentation.
Also adding a use case for installing a cluster on bare metal machines
exclusively.
A couple of improvements to the openstack BM workers doc:
- Capitalize acronyms
- Fixed links
- Fixed typos
- Point to supported documentation for customizing OS image
