daemon/containerd: add more TODO's for image list, and reformat
daemon/containerd: add more TODO's for image list, and reformat

Reformat/rename some bits to better align with the old implementation for
easier comparing, and add some TODOs for tracking issues on remaining work.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

moby/moby,moul/docker,cpuguy83/docker,thaJeztah/docker,jimjag/docker,mahak/docker,moul/docker,thaJeztah/docker,trebonian/docker,jimjag/docker,cpuguy83/docker,Mokolea/docker,thaJeztah/docker,konstruktoid/docker-upstream,moby/moby,Ramzec/docker,Mokolea/docker,thaJeztah/docker,mahak/docker,jimjag/docker,Mokolea/docker,konstruktoid/docker-upstream,moby/moby,Ramzec/docker,Mokolea/docker,Ramzec/docker,moul/docker,cpuguy83/docker,moul/docker,trebonian/docker,konstruktoid/docker-upstream,mahak/docker,Ramzec/docker,cpuguy83/docker,trebonian/docker,konstruktoid/docker-upstream,mahak/docker,jimjag/docker,moby/moby,trebonian/docker