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.

nextcloud/k8s/external-service.yaml

@@ -0,0 +1,49 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: nextcloud-apache
+  namespace: nextcloud
+spec:
+  ports:
+  - port: 11000
+    targetPort: 11000
+---
+apiVersion: discovery.k8s.io/v1
+kind: EndpointSlice
+metadata:
+  name: nextcloud-apache
+  namespace: nextcloud
+  labels:
+    kubernetes.io/service-name: nextcloud-apache
+addressType: IPv4
+ports:
+- port: 11000
+  protocol: TCP
+endpoints:
+- addresses:
+  - "192.168.49.1"
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nextcloud-aio
+  namespace: nextcloud
+spec:
+  ports:
+  - port: 8080
+    targetPort: 8080
+---
+apiVersion: discovery.k8s.io/v1
+kind: EndpointSlice
+metadata:
+  name: nextcloud-aio
+  namespace: nextcloud
+  labels:
+    kubernetes.io/service-name: nextcloud-aio
+addressType: IPv4
+ports:
+- port: 8080
+  protocol: TCP
+endpoints:
+- addresses:
+  - "192.168.49.1"