Feat/scs minor versions

[jschoone]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• squash commits
• include documentation
• add unit tests

[jschoone]

Most things work so far, still in heavy testing.
Replaces #248, #252, #255 if everything's fine

[jschoone]

• Matrix should be added to the docs automatically

[jschoone]

The stack.yaml is a merge of csctl and versions.yaml
The old files can still be readded to the older versions to keep them backwards compatible also to keep csctl working, but I think using oras etc directly in a script is a much more lightweight solution

[Nils98Ar]

@jschoone @garloff

I have tested the scripts and cluster stack, added scs2 changes, updates and some fixes + cilium native routing and kube-proxy replacement (starting with K8s 1.35). Our dev clusters are running on this cluster-stack in with K8s version 1.35 now.

The most important for updating and releasing new cluster stacks are now:

sudo nix develop
source .envrc
./hack/update.sh
./hack/build.sh --all --publish

[Nils98Ar]

Our cluster manifests look something like this, so this is what I used to test the cluster stacks (i have replaced some values with dummys/examples/placeholders):

---
apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
metadata:
  name: "cluster-1"
  namespace: "tenant-1"
  labels:
    managed-secret: clouds-yaml
spec:
  clusterNetwork:
    pods:
      cidrBlocks:
        - 10.251.0.0/16
    serviceDomain: cluster.local
    services:
      cidrBlocks:
        - 10.252.0.0/16
  topology:
    variables:
      - name: networkExternalID
        value: "external-network-id"
      - name: nodeCIDR
        value: "10.253.2.0/24"
      - name: dnsNameservers
        value: ["9.9.9.9","149.112.112.112"]
      - name: apiServerAllowedCIDRs
        value: ["192.168.178.0/24"]
      - name: apiServerLoadBalancer
        value: "octavia-amphora"
      - name: registryMirrors
        value: [{hostnameUpstream: registry-1.docker.io, urlUpstream: 'https://registry-1.docker.io', urlMirror: 'https://mirror.foo.bar/v2/docker.io'}, {hostnameUpstream: index.docker.io, urlUpstream: 'https://registry-1.docker.io', urlMirror: 'https://mirror.foo.bar/v2/docker.io'}, {hostnameUpstream: docker.io, urlUpstream: 'https://registry-1.docker.io', urlMirror: 'https://mirror.foo.bar/v2/docker.io'}, {hostnameUpstream: gcr.io, urlUpstream: 'https://gcr.io', urlMirror: 'https://mirror.foo.bar/v2/gcr.io'}, {hostnameUpstream: ghcr.io, urlUpstream: 'https://ghcr.io', urlMirror: 'https://mirror.foo.bar/v2/ghcr.io'}, {hostnameUpstream: k8s.gcr.io, urlUpstream: 'https://k8s.gcr.io', urlMirror: 'https://mirror.foo.bar/v2/k8s.gcr.io'}, {hostnameUpstream: quay.io, urlUpstream: 'https://quay.io', urlMirror: 'https://mirror.foo.bar/v2/quay.io'}, {hostnameUpstream: registry.gitlab.com, urlUpstream: 'https://registry.gitlab.com', urlMirror: 'https://mirror.foo.bar/v2/registry.gitlab.com'}, {hostnameUpstream: registry.k8s.io, urlUpstream: 'https://registry.k8s.io', urlMirror: 'https://mirror.foo.bar/v2/registry.k8s.io'}]
    classRef:
      name: openstack-scs-1-35-v1
      namespace: cluster-stacks
    version: v1.35.3
    controlPlane:
      replicas: 3
      variables:
        overrides:
          - name: flavor
            value: "SCS-2V-4-20s"
          - name: serverGroupID
            value: "<cluster-1-controller-group-id>"
          - name: rootDisk
            value: 0
    workers:
      machineDeployments:
        - class: default-worker
          failureDomain: nova
          name: worker
          replicas: 3
          variables:
            overrides:
              - name: flavor
                value: "SCS-4V-16-100s"
              - name: serverGroupID
                value: "<cluster-1-worker-group-id>"
              - name: rootDisk
                value: 0