CI cleanup: Uploading of images for CAPO upgrade tests

[lentzi90]

From #2792 (comment)

The things we can cleanup is this:

• Image upload:

  cluster-api-provider-openstack/scripts/ci-e2e.sh

  Lines 100 to 104 in b9fa78b

  	retry 10 10 scp $(get_ssh_common_args) "${container_archive}" "cloud@${CONTROLLER_IP}:capo-e2e-image.tar"
  	retry 10 10 $(get_ssh_cmd) ${CONTROLLER_IP} -- sudo chown root:root capo-e2e-image.tar
  	retry 10 10 $(get_ssh_cmd) ${CONTROLLER_IP} -- sudo chmod u=rw,g=r,o=r capo-e2e-image.tar
  	retry 10 10 $(get_ssh_cmd) ${CONTROLLER_IP} -- sudo mkdir -p /var/www/html
  	retry 10 10 $(get_ssh_cmd) ${CONTROLLER_IP} -- sudo mv capo-e2e-image.tar /var/www/html/capo-e2e-image.tar

• Image download patches: https://github.com/kubernetes-sigs/cluster-api-provider-openstack/blob/main/test/e2e/data/kustomize/components/upgrade-patches/ci-hack-kct.yaml

These were used to upload the CAPO image that is being tested into the management cluster. All other tests use kind clusters where the image is loaded directly, but the clusterctl upgrade was using a full CAPO cluster so we used this to get the image into it.

Edit: I forgot about the self-hosted test! It still needs these, but we should adjust the naming...