As a minimum, we would like to maintain generic garbage collection of
containerd resources. This includes images, bundles, containers and
arbitrary content.
The included implementation is just a textbook toy that we can use to
inform the requirements of gc. It implements a simple, stack-based
tricolor algorithm. Nothing special.
Mostly, this is to ensure we think about garbage collection from the
start, rather than as an afterthought or follow on feature.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
