feat(docker): discourse container requires docker

This utility state may be removed from here in the future to use a
dedicated formula.

discourse/docker/clean.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+include:
+  - .service.clean
+  - .package.clean

discourse/docker/init.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+include:
+  - .package
+  - .service

discourse/docker/package/clean.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+{#- Get the `tplroot` from `tpldir` #}
+{%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_docker_service_clean = tplroot ~ '.docker.service.clean' %}
+{%- from tplroot | path_join("map.jinja") import discourse with context %}
+
+include:
+  - {{ sls_docker_service_clean }}
+
+discourse-docker-package-clean-pkg-removed:
+  pkg.removed:
+    - name: docker.io
+    - require:
+      - sls: {{ sls_docker_service_clean }}

discourse/docker/package/init.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+include:
+  - .install

discourse/docker/package/install.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+discourse-docker-package-install-pkg-installed:
+  pkg.installed:
+    - name: docker.io

discourse/docker/service/clean.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+{#- Get the `tplroot` from `tpldir` #}
+{%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_discourse_clean = tplroot ~ '.clean' %}
+{%- from tplroot | path_join("/map.jinja") import discourse with context %}
+
+include:
+  - {{ sls_discourse_clean }}
+
+discourse-docker-service-clean-service-dead:
+  service.dead:
+    - name: docker
+    - enable: False
+    - require:
+      - sls: {{ sls_discourse_clean }}

discourse/docker/service/init.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+include:
+  - .running

discourse/docker/service/running.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+{#- Get the `tplroot` from `tpldir` #}
+{%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_docker_package_install = tplroot ~ '.docker.package.install' %}
+{%- from tplroot | path_join("map.jinja") import discourse with context %}
+
+include:
+  - {{ sls_docker_package_install }}
+
+discourse-docker-service-running-service-running:
+  service.running:
+    - name: docker
+    - enable: True
+    - require:
+      - sls: {{ sls_docker_package_install }}