feat(k8s): add K8s manifests for all homelab services

traefik, gitea, adguard, nextcloud, errorpages, homepages,
uptime-kuma, kener, checkmk, headscale, dockmon, metube,
downtify, portainer, netronome, userbot

Includes Helm values, deployments, services, ingress routes,
configmaps, secrets (placeholders), postgres statefulsets,
kustomize overlays, and Traefik dynamic configuration.

kener/k8s/secrets.yaml.example

@@ -0,0 +1,8 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: kener-secrets
+  namespace: kener
+type: Opaque
+stringData:
+  KENER_SECRET_KEY: ""