Implement the `ovirt_vm_graphics_consoles` resource

[janosdebugs]

Please describe what you would like to see

We need a way to remove all graphics consoles from a VM after creation. Depends on oVirt/go-ovirt-client#192

Please describe the solution you'd like

In keeping with Terraform semantics, we need a resource that manages graphics consoles on a VM:

resource "ovirt_vm_graphic_consoles" "master" {
  vm_id = var.vm_id
  graphics_console {
    // Graphics console parameters
  }
  graphics_console {
    // Graphics console parameters
  }
}

However, at this time it is enough if we support exactly 0 graphics consoles as we only need to remove them.

Please describe your use case

We need to remove all graphics consoles from a VM for high performance. See openshift/installer#5867 for details.