feat(package): discourse deployment use `netstat`

This utility is provided by `net-tools` which is required by
`cloud-init`, so there is no clean of this package.

discourse/net-tools/init.sls

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

discourse/net-tools/install.sls

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