Upgrade CAPI to v1.3.5 and CAPO to v0.7.1

Created by: matofeder

This PR updates the following:

• Cluster API provider (CAPI) version from v1.6.2 to v1.3.5
• OpenStack provider for CAPI (CAPO) version from v0.6.4 to v0.7.1
• CAPO API version in cluster-template.yaml from v1alpha5 to v1alpha6

Note1: Tested with Ubuntu22.04 and Ubuntu20.04

Note2: There are no further changes between CAPO v1alpha5 and v1alpha6:

$ diff <(curl -s https://raw.githubusercontent.com/kubernetes-sigs/cluster-api-provider-openstack/main/kustomize/v1alpha5/default/cluster-template.yaml) <(curl -s https://raw.githubusercontent.com/kubernetes-sigs/cluster-api-provider-openstack/main/kustomize/v1alpha6/default/cluster-template.yaml)
12c12
<     apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
>     apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
20c20
< apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
> apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
46c46
<       apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
>       apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
97c97
< apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
> apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
133c133
<         apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
>         apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
136c136
< apiVersion: infrastructure.cluster.x-k8s.io/v1alpha5
---
> apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6

Closes #330 (closed)