Add hostname to restic containers

Will pass through the hostname to any snapshots set up.
The hostname is _not_ derived from the random docker container string
but instead takes the name of the _host_ on which docker is running
(from ansible facts).

The hostname in combination with the tag should point to the correct
host -> stack which is being backed up.

roles/paperless/templates/docker-compose.yaml.j2

@@ -68,6 +68,7 @@ services:
 {% if restic_enable is not undefined and not false and stack_paperless_restic_enable is not undefined and not false %}
   backup:
     image: mazzolino/restic
+    hostname: "{{ ansible_hostname }}"
     environment:
       TZ: "{{ restic_tz }}"
       BACKUP_CRON: "{{ stack_paperless_restic_cron }}"