AlertScript for alert notification from Zabbix 2.x

@mihasya Here is a Zabbix 2 AlertScript integration for Opsmatic. Setup in Zabbix is a little bit like falling down the rabbit hole, as integration with scripts assumes email-like interfaces. I've put together step-by-step instructions that worked for us in the readme. Tested in Zabbix 2.x, but there are a lot of dot releases out there, so there may be small tweaks. Uses pretty vanilla features and focus was on 2.2+.

Patterned after a clone of Nagios integration, so same requirements.