feat(deployment): discourse is deployed from git repository

The `discourse.git.package` state may be removed in the future to use
a dedicated formula.

discourse/git/clean.sls

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

discourse/git/clone.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+{#- Get the `tplroot` from `tpldir` #}
+{%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_git_package_install = tplroot ~ '.git.package.install' %}
+{%- from tplroot | path_join("map.jinja") import discourse with context %}
+
+include:
+  - {{ sls_git_package_install }}
+
+discourse-git-clone-git-latest:
+  git.latest:
+    - name: {{ discourse | traverse('docker-git-url') }}
+    - target: {{ discourse.directory }}
+    - require:
+      - sls: {{ sls_git_package_install }}

discourse/git/init.sls

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

discourse/git/package/clean.sls

+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+discourse-git-package-install-pkg-removed:
+  pkg.removed:
+    - name: git

discourse/git/package/init.sls

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

discourse/git/package/install.sls

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