Install ElastAlert on log.gitlap.com

ElastAlert would be an excellent resource for the one-off events that happen occasionally, such as the recent NFS errors or rsyslog freezes. I'd like to get it installed on the log server so we can write custom rules as needed.

https://github.com/Yelp/elastalert

Installation will require a custom user and init script to run it as a daemon. That means a chef recipe.