refstack: capture container logs to disk

We have setup rsyslogd/logrotate to handle anything with docker- tags
to be persisted to disk in /var/log/containers.  Set this up here so
we keep track of the mariadb and refstack logs.

Change-Id: I760cfeb7226f79986fbf9d7dbc5f899fc87a0cd1

playbooks/roles/refstack/templates/docker-compose.yaml.j2

@@ -14,6 +14,11 @@ services:
       MYSQL_PASSWORD: "{{ refstack_db_password }}"
     volumes:
       - /var/lib/refstack/db:/var/lib/mysql
+    logging:
+      driver: syslog
+      options:
+        tag: "docker-mariadb"
+
   refstack-api:
     depends_on:
       - mariadb
@@ -24,3 +29,7 @@ services:
       - /var/lib/refstack/etc/refstack.conf:/etc/refstack.conf
       - /var/lib/refstack/etc/config.json:/refstack-ui/app/config.json
       - /var/lib/refstack/data:/var/run/data
+    logging:
+      driver: syslog
+      options:
+        tag: "docker-refstack-api"