Add logstash-forwarder

This adds support for forwarding the elasticsearch request logs into another deployment (like we have setup on the old, active cluster).

I suppose we could make it forward every single monit stdout/stderr log and every other vcap-related log file, but I wasn't sure if we want to do that?

http://kibana-meta-logsearch-io.monitor-cloud.cityindextest5.co.uk/index.html#dashboard/temp/QDoiH4UWR9q8VhAB8z4L7w