Cluster Creation Fails on Nil Pointer with Missing VSphereDatacenterConfig

[jonathanmeier5]

In v0.16.0 if a cluster spec is missing its VSphereDatacenterConfig the create cluster command fails on a nil pointer error:

goroutine 1 [running]:
github.com/aws/eks-anywhere/pkg/providers/vsphere.(*vsphereProvider).SetupAndValidateCreateCluster(0xc000d4f880, {0x3c3e7f0, 0xc0000540c8}, 0xc0007937c0)
        /home/ubuntu/workplace/eks-anywhere/pkg/providers/vsphere/vsphere.go:294 +0x16c
github.com/aws/eks-anywhere/pkg/validations/createcluster.(*ValidationManager).generateCreateValidations.func4()
        /home/ubuntu/workplace/eks-anywhere/pkg/validations/createcluster/createcluster.go:72 +0xae
github.com/aws/eks-anywhere/pkg/validations.(*Runner).Run(0x55c0c30?)
        /home/ubuntu/workplace/eks-anywhere/pkg/validations/runner.go:24 +0x42
github.com/aws/eks-anywhere/pkg/validations/createcluster.(*ValidationManager).Validate(0xc0009f5740, {0x3c3e7f0, 0xc0000540c8})
        /home/ubuntu/workplace/eks-anywhere/pkg/validations/createcluster/createcluster.go:41 +0x225
github.com/aws/eks-anywhere/cmd/eksctl-anywhere/cmd.(*validateOptions).validateCreateCluster(0x558fee0, 0x55694c0, {0x0?, 0x0?, 0x0?})
        /home/ubuntu/workplace/eks-anywhere/cmd/eksctl-anywhere/cmd/validatecreatecluster.go:102 +0x7ca
github.com/spf13/cobra.(*Command).execute(0x55694c0, {0xc0005dc1c0, 0x4, 0x4})
        /home/ubuntu/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:916 +0x862
github.com/spf13/cobra.(*Command).ExecuteC(0x5567800)
        /home/ubuntu/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:1044 +0x3bd
github.com/spf13/cobra.(*Command).Execute(...)
        /home/ubuntu/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:968
github.com/spf13/cobra.(*Command).ExecuteContext(...)
        /home/ubuntu/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:961
github.com/aws/eks-anywhere/cmd/eksctl-anywhere/cmd.Execute()
        /home/ubuntu/workplace/eks-anywhere/cmd/eksctl-anywhere/cmd/root.go:65 +0x54
main.main()
        /home/ubuntu/workplace/eks-anywhere/cmd/eksctl-anywhere/main.go:29 +0x125
exit status 2

Steps to reproduce:

1. Start with a working cluster config
2. Delete the apiVersion field in the VSphereDatacenterConfig object like so:

kind: VSphereDatacenterConfig
metadata:
  name: my-datacenter
spec:
  datacenter: "my-DC"
  insecure: true
  network: "/my-DC/network/foo"
  server: "my-dc-endpoint"
  thumbprint: "XXXX"