Add wallabag docker deployment role

Added role of wallabag. Can take a subdomain alias to be presented on a
different uri than its stack name.

All services contain a healthcheck for docker swarm to be informed of
their status.

Copy whoami template to wallabag role

Change non-domain domain name to localhost

Fix correct handler notify naming

Allow setting different subdomain alias than name

Add meta information

roles/wallabag/tasks/main.yml

@@ -0,0 +1,25 @@
+---
+## install wallabag container
+- name: Check upstream status
+  community.docker.docker_container_exec:
+    container: "{{ caddy_container_id }}"
+    command: >
+      curl localhost:2019/id/{{ stack.name }}_upstream/
+  register: result
+  changed_when: (result.stdout | from_json) != (lookup('template', 'upstream.json.j2') | from_yaml)
+  become: yes
+  notify: "update wallabag upstream"
+
+- name: Deploy wallabag to swarm
+  community.general.docker_stack:
+    name: "{{ stack.name }}"
+    state: present
+    prune: yes
+    compose:
+      - "{{ stack.compose }}"
+  when: stack is defined
+  become: yes
+  tags:
+    - docker-swarm
+  notify: "update wallabag upstream"
+