Juju Action for Image Cleanup

[lazypower]

This gets tricky as data containers can be present on the host, and destructive actions will likely nuke non-running data containers.

I suppose we could create an action, and leave it up to the author to be as destructive as they wish to be with the action. Proper documentation will be provided on what its doing, what commands its executing, and why this may or may not be disastrous.