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/README.md

@@ -0,0 +1,42 @@
+# wallabag
+
+A very simple service application stack role which can be used to base other roles off of.
+Contains only a single deployed image and a couple of simple variables to set.
+
+## Variables
+
+```
+wallabag_upstream_file_dir: "{{ docker_stack_files_dir }}/{{ stack.name }}"
+```
+
+The on-target directory where the proxy configuration file should be stashed.
+
+```
+wallabag_use_https: true
+```
+
+Whether the service should be reachable through http (port 80) or through https (port 443) and provision an https certificate. Usually you will want this to stay `true`.
+
+```
+wallabag_version: latest
+```
+
+The docker image version to be used in stack creation.
+
+## Internal variables
+
+```
+stack:
+  name: wallabag
+  compose: "{{ lookup('template', 'docker-stack.yml.j2') | from_yaml }}"
+```
+
+The name of the stack to be provisioned and the compose file to be used.
+See caddy ReadMe for configuration.
+
+```
+stack_image: "wallabag/wallabag"
+```
+
+The docker hub image to be use in provisioning.
+