This uses new logstash conf.d features to properly link in the
configuration from the logstash-filters repo. This should make
configuring logstash far more flexible and reconsumable.
Change-Id: Ia304eb7e73c82ca5ce85967fbf442bb4bc5f8b7a
Depends-On: Icbca7a6ba0c5a94a273ef158f707311b588483fd