Changes to send data from Graphite to Zabbix

This also creates the required elements (hosts, items, triggers etc) in Zabbix based on definitions from users.
We should be able to run through zabbix as external check. In order to define an external check item, a zabbix host interface need to be defined and its id need to be passed to the external check item definition. Currently ruby zabbixapi doesn't support host interface api call. Another request apart from action api to the ruby zabbixapi team. Any other tools we want to look at other than cron.