as a consequence, removed usage of email_service library.
Updated the meaning for site.email to be sender email addressed.
Added notification.email to set the email address that will received system email notification.
Note that CMS_SETUP provides locations set by default or from configuration file.
Now theme related resources can be found under site/modules/$mod_name/... or site/themes/$theme/modules/...
so only theme related resources can be overriden for now.