Proposal: Initial images proposal

This is a proposal to add a higher level image component that can keep track of Docker image repositories, images, and image metadata.
And there's nothing really that allows an image consumer (say, an organization that wants to use a Redis image contributed by a company upstream, or antirez) to control / manage the images coming from the upstream without creating their own images, or from easily switching from one producer of images to another (say, from antirez to an image stream hosted by centos).