added node ip autodetection
added node ip autodetection

Manager now auto-detects the address that an agent connects to the cluster
from and stores it. This is useful for many kinds of internal cluster
management tools.

Signed-off-by: Drew Erny <83d780db39fae693cf18623ace93c7ec0dc91590@docker.com>

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