Improve networks

Create a single external network called "external".
Create container-specific networks.
Only a few containers need access to these.
So far: openldap, postgres.

roles/authelia/tasks/main.yml

@@ -17,8 +17,8 @@
     ports:
       - "9091:9091"
     networks:
-      - name: bridge
-      - name: nginx-internal
+      - name: external
+      - name: openldap
     volumes:
       - "{{ data_folder }}/authelia:/config"
 - name: copy nginx endpoint conf