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.

adguardhome/k8s/secrets.yaml.example

@@ -0,0 +1,10 @@
+kubectl apply -f k8s/namespace.yaml && \
+kubectl create secret tls adguard-certs -n adguard \
+  --cert=certs/fullchain.pem \
+  --key=certs/privkey.pem --dry-run=client -o json > \
+  k8s/secrets.yaml
+
+#  OR WITH NO FILE CREATION:
+kubectl create secret tls adguard-certs -n adguard \
+  --cert=certs/fullchain.pem --key=certs/privkey.pem \
+  --save-config