Add out_elasticsearch setting page

Follow the EFK stack movement.
https://www.digitalocean.com/community/tutorials/elasticsearch-fluentd-and-kibana-open-source-log-search-and-visualization

![2014-08-13 18 11 17](https://cloud.githubusercontent.com/assets/499680/3903275/dd7f37e4-22c9-11e4-93eb-ac383a1f5030.png)

![2014-08-13 18 12 41](https://cloud.githubusercontent.com/assets/499680/3903282/04f81444-22ca-11e4-9827-909cbc75f919.png)