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 can run the script using the external check item of Zabbix. But zabbixapi gem currently doesn't support the creation of host interface in Zabbix which is required to define an external check item. We can make a request to the zabbixapi team. In the meantime can we go with cron or do we want to investigate any other tool for scheduling.