remove graylog (no longer FOSS, uses SSPL)

- https://github.com/Graylog2/graylog2-server/blob/master/LICENSE
- https://blog.opensource.org/the-sspl-is-not-an-open-source-license/

README.md

@@ -466,7 +466,6 @@ _See also: [IT Asset Management]([Ralph](#it-asset-management))_
 - [Fluentd](http://www.fluentd.org/) - Log Collector and Shipper. ([Source Code](https://github.com/fluent/fluentd)) `Apache-2.0` `Ruby`
 - [Flume](https://flume.apache.org/) - Distributed log collection and aggregation system. ([Source Code](https://github.com/apache/flume)) `Apache-2.0` `Java`
 - [GoAccess](http://goaccess.io/) - Real-time web log analyzer and interactive viewer that runs in a terminal or through the browser. ([Source Code](https://github.com/allinurl/goaccess)) `MIT` `C`
-- [Graylog](https://www.graylog.org/) - Pluggable Log and Event Analysis Server with Alerting options.
 - [Hindsight](http://mozilla-services.github.io/hindsight/) - Stream processing system which may be used for log aggregation (Replaces Heka).
 - [Kibana](https://www.elastic.co/products/kibana) - Visualize logs and time-stamped data.
 - [Logstash](https://www.elastic.co/products/logstash) - Tool for managing events and logs.