zabbix user support

[hairmare]

This is not about the puppet resource "user" (it's only for system users). I have these plans:

• setup zabbix so it grabs users from ldap (or other directories)
• add a fallback user with read access (for when ldap is down)

[hairmare]

This: http://www.zabbix.com/wiki/howto/config/active_directory_authentication

Not sure if supported n API.