Add initial configuration and templates for feedstack role.

vars/containers/watchtower.yml

@@ -0,0 +1,16 @@
+---
+watchtower:
+
+  # Define the name of this container.
+  name: "feedstack-watchtower"
+
+  # Define the docker image to be used for this container.
+  image: "{{ feedstack_watchtower_container_image }}:{{ feedstack_watchtower_container_tag }}"
+
+  # Define the path where application data for this container will be stored.
+  appdata_directory: "{{ docker_appdata_directory }}/watchtower"
+
+  # Define the volumes that should be mounted into the container.
+  volumes:
+    - "/var/run/docker.sock:/var/run/docker.sock"
+...