If we don't want to have separate registry tags by architecture (EWWWW),
we need to be able to build multiarch docker images. This is pretty
simple, and just requires making a manifest pointing to each of the
component images.
I was *going* to just do this API prodding with manifest-tool, but it
doesn't support putting metadata on the outer manifest, which is
actually kind of a problem because it then doesn't render the metadata
on github. So I guess we get a simple little containers API
implementation that is 90% auth code.
Change-Id: I8bdd118d4cbc13b23224f2fb174b232432686bea
jade