icinga2x-graylog2: Add Ruby script to add inputs and streams.
icinga2x-graylog2: Make sure to install Elasticsearch 1.3.4.

Previously an Elasticsearch 1.0.x got installed.
icinga2x-graylog2: Let Elasticsearch listen on localhost only.
icinga2x-graylog2: Increase max file descriptor limit for elasticsearch user.

This avoids warnings in Graylog2.