a bash script to clean dangling docker images across all bd-swarm vms.

can added as a cron job.

dangling docker images, something like:

clowder/extractors-river <none> b7e0590139ad 3 months ago 633MB
clowder/extractors-opencv-profiles <none> 798a08871363 3 months ago 454MB
clowder/extractors-plantcv <none> 7b86822b42bc 3 months ago 1.29GB
clowder/extractors-opencv-faces <none> 7df78848d281 3 months ago 454MB
clowder/extractors-opencv-eyes <none> da3355c38606 3 months ago 454MB
clowder/extractors-opencv-closeups <none> 3cf3ccb1a109 3 months ago 454MB
clowder/extractors-siegfried <none> 6c32b4e97a2b 3 months ago 234MB
clowder/extractors-office-preview <none> 0c4110df8655 3 months ago 978MB
clowder/extractors-digest <none> 3da586fa5164 3 months ago 162MB
clowder/extractors-audio-preview <none> c3ca961205b4 3 months ago 184MB
clowder/extractors-image-preview <none> 31efb3c5c015 3 months ago 300MB