Option to deploy harbor

Created by: garloff

We have the k8s-harbor repository that can be used to automate the deployment of harbor registry on SCS clusters. We should offer this as an option. To make it work, we need to:

• deploy_flux
• understand how to create working certs using cert-manager (which will likely need updating)
• create a testable setup for CI purposes and document how prod setups would work

The k8s-harbor repo references a comparably old version of harbor, we should also check whether we can update here.