build: add Nutanix infra provider

[dkoshkin]

Deploy CAPX and the default clusterclass and templates. This will unblock all of us working on CAPX related work.

I also added the versions to deploy in make/clusterctl.mk to match the synced API version, otherwise clusterctl will fetch the latest stable version (in the case of CAPX) or a newer provider version that doesn't match the API.

[dkoshkin]

➜  capi-runtime-extensions git:(dkoshkin/build-use-same-infra-provider-versions) ✗ k get providers -A
NAMESPACE                           NAME                     AGE    TYPE                     PROVIDER      VERSION
caaph-system                        addon-helm               6m2s   AddonProvider            helm          v0.1.1-alpha.1
capa-system                         infrastructure-aws       6m2s   InfrastructureProvider   aws           v2.4.0
capd-system                         infrastructure-docker    6m2s   InfrastructureProvider   docker        v1.6.3
capi-kubeadm-bootstrap-system       bootstrap-kubeadm        6m3s   BootstrapProvider        kubeadm       v1.6.3
capi-kubeadm-control-plane-system   control-plane-kubeadm    6m3s   ControlPlaneProvider     kubeadm       v1.6.3
capi-system                         cluster-api              6m3s   CoreProvider             cluster-api   v1.6.3
capx-system                         infrastructure-nutanix   6m2s   InfrastructureProvider   nutanix       v1.4.0-alpha.1

➜  capi-runtime-extensions git:(dkoshkin/feat-deploy-capx-infra-provider) k get clusterclass
NAME                  AGE
aws-quick-start       5m21s
docker-quick-start    5m21s
nutanix-quick-start   5m21s

[deepakm-ntnx]

these changes are already part of #6