Add .dockerignore support
Add .dockerignore support

Fixes #2224

Docker-DCO-1.1-Signed-off-by: Travis Cline <travis.cline@gmail.com> (github: tmc)

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