Add a postgresql_client role

The role is empty but is used to explicitly define servers that have
access rights to all PostgreSQL databases and users

roles/ejabberd.rb

@@ -1,10 +1,12 @@
 name "ejabberd"
 
 default_run_list = %w(
+  role[postgresql_client]
   kosmos-ejabberd::default
 )
 
 production_run_list = %w(
+  role[postgresql_client]
   kosmos-ejabberd::default
   kosmos-ejabberd::letsencrypt
   kosmos-ejabberd::backup

roles/gitea.rb

@@ -1,6 +1,7 @@
 name "gitea"
 
 run_list %w(
+  role[postgresql_client]
   kosmos_gitea::default
   kosmos_gitea::backup
 )

roles/postgresql_client.rb

@@ -0,0 +1,5 @@
+# This role is used by the kosmos-postgresql::default recipe to add access
+# rules to every server that is a PostgreSQL client
+name "postgresql_client"
+
+run_list []