Connect Stalwart to Authentik LDAP for user authentication

- Add LDAP directory backend in Stalwart pointing to ldap.rubenhensen.nl
- Expose Authentik LDAP outpost externally via LoadBalancer service
- Add ldap.rubenhensen.nl DNS record

authentik/ldap-outpost-lb.yaml

@@ -0,0 +1,18 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: ldap-outpost-external
+  namespace: authentik
+spec:
+  type: LoadBalancer
+  selector:
+    app.kubernetes.io/name: ak-outpost-ldap-outpost
+  ports:
+    - name: ldap
+      port: 389
+      targetPort: 3389
+      protocol: TCP
+    - name: ldaps
+      port: 636
+      targetPort: 6636
+      protocol: TCP