Add k8s deployment, standalone app Dockerfile.

Tested with Rancher k3s. See k8s/README.md for site configuration and
deployment instructions.

Add cert-manager, tls, remote headscale script.

k8s/postgres/postgres-statefulset.yaml

@@ -0,0 +1,49 @@
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: postgres
+spec:
+  serviceName: postgres
+  replicas: 1
+  selector:
+    matchLabels:
+      app: postgres
+  template:
+    metadata:
+      labels:
+        app: postgres
+    spec:
+      containers:
+      - name: postgres
+        image: "postgres:13"
+        imagePullPolicy: IfNotPresent
+        env:
+        - name: POSTGRES_PASSWORD
+          valueFrom:
+            secretKeyRef:
+              name: postgresql
+              key: password
+        - name: POSTGRES_USER
+          value: headscale
+        ports:
+        - name: postgres
+          protocol: TCP
+          containerPort: 5432
+        livenessProbe:
+          tcpSocket:
+            port: 5432
+          initialDelaySeconds: 30
+          timeoutSeconds: 5
+          periodSeconds: 15
+        volumeMounts:
+        - name: pgdata
+          mountPath: /var/lib/postgresql/data
+  volumeClaimTemplates:
+  - metadata:
+      name: pgdata
+    spec:
+      storageClassName: local-path
+      accessModes: ["ReadWriteOnce"]
+      resources:
+        requests:
+          storage: 1Gi