Update CLI docs and add opts/config.go
Update CLI docs and add opts/config.go

Signed-off-by: Aaron Lehmann <8ecfc6017a87905413dcd7d63696a2a4c351b604@docker.com>

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