Add contrib/nuke-graph-directory.sh script to clean out old /var/lib/docker directories much more easily

Signed-off-by: Andrew Page <admwiggin@gmail.com>
Cleanup: extract bindmount spec parsing

Docker-DCO-1.1-Signed-off-by: Brian Goff <cpuguy83@gmail.com> (github: cpuguy83)
Merge pull request #7446 from cpuguy83/cleanup_extract_bindmount_spec_parsing

Cleanup: extract bindmount spec parsing
Merge pull request #7423 from tianon/nuclear-_-weapons--we-got-the-bomb

Add contrib/nuke-graph-directory.sh script to clean out old /var/lib/docker directories much more easily