add UDP GELF logging-driver
add UDP GELF logging-driver

allows to send container logs to Graylog or Logstash.

Signed-off-by: Marius Sturm <38edb439dbcce85f0f597d90d338db16e5438073@graylog.com>

riyazdf/cli,thaJeztah/cli,dnephin/cli,ashfall/cli,Zebrilee/cli,riyazdf/cli,e11137/cli,allencloud/cli,redpanda/cli,thaJeztah/cli,Zebrilee/cli,redpanda/cli,e11137/cli,cpuguy83/cli,dnephin/cli,docker/cli,docker/cli,cpuguy83/cli,allencloud/cli,ashfall/cli