Add PostgreSQL primary support to the kosmos-ejabberd cookbook

* Move the PostgreSQL user and database creation to a pg_db recipe
* Generate access rights for the ejabberd servers in the pg_db recipe
* Connect to the PostgreSQL primary instead of localhost

Refs #180

site-cookbooks/kosmos-ejabberd/templates/vhost.yml.erb

@@ -7,7 +7,7 @@ certfiles:
 host_config:
   "<%= @host[:name] %>":
     sql_type: pgsql
-    sql_server: "localhost"
+    sql_server: "<%= @sql_server %>"
     sql_database: "<%= @host[:sql_database] %>"
     sql_username: "ejabberd"
     sql_password: "<%= @pgsql_password %>"