Vendor the external cookbooks

Knife-Zero doesn't include Berkshelf support, so vendoring everything in
the repo is convenient again

cookbooks/postfix/templates/default/virtual_aliases.erb

@@ -0,0 +1,9 @@
+#
+# Auto-generated by Chef.
+# Local modifications will be overwritten.
+#
+# See man 5 virtual for format
+
+<% node['postfix']['virtual_aliases'].each do |key, value| %>
+<%= key %> <%= value %>
+<% end unless node['postfix']['virtual_aliases'].nil? %>