fix: drop ConfigMap patching and CI tests

[oleksandr-nc]

EDITED: Started out as a fix for a CoreDNS crashloop that hit us on k3s , but after investigating and trying two approaches, the cleanest answer turned out to be "just remove the whole cluster-wide DNS patcher" as coredns-custom is a k3s/RKE convention. It is not universal.

To restore the state of system how it would be after this PR is merged, it is required to:

for k3s:

kubectl delete configmap coredns-custom -n kube-system --ignore-not-found

kubectl delete configmap coredns -n kube-system
kubectl rollout restart deployment coredns -n kube-system
kubectl get configmap coredns -n kube-system -o jsonpath='{.data.Corefile}' | grep -c nextcloud - should print 0

for kind:

kubectl delete configmap coredns-custom -n kube-system --ignore-not-found

kubectl apply -f - <<'EOF'
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health {
           lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        prometheus :9153
        forward . /etc/resolv.conf {
           max_concurrent 1000
        }
        cache 30 {
           disable success cluster.local
           disable denial cluster.local
        }
        loop
        reload
        loadbalance
    }
EOF

kubectl rollout restart deployment coredns -n kube-system
kubectl rollout status deployment coredns -n kube-system --timeout=60s

---

1. CoreDNS host-alias patching was broken on k3s

   _k8s_ensure_coredns_host_aliases patches the main coredns ConfigMap in kube-system to make HP_K8S_HOST_ALIASES resolve cluster-wide. The regex hosts\s*\{[^}]*\} only matches the argumentless form of the hosts plugin - k3s ships with hosts /etc/coredns/NodeHosts { ... }, which the regex misses. HaRP then falls through to the "insert before forward ." branch and appends a second hosts {} block inside the same server block.

   Fix: stop writing to the operator-owned coredns ConfigMap entirely. Write a standalone .server file into kube-system/coredns-custom instead - that's the ConfigMap k3s's CoreDNS Deployment already mounts at /etc/coredns/custom/ (optional: true) and imports via import /etc/coredns/custom/*.server. Each alias becomes its own zone with a small hosts { ... } block, so there's no way to collide with any plugin in the main server block.

2. CI: deploy workflows copied from AppAPI

[kyteinsky]

works with kind ✔️
docs would need updates too.