Move configurations into a single file.
Abstract download manager in pull config.
Add supports for schema2 only and schema2 type checking.
Add interface for providing push layers.
Abstract image store to generically handle configurations.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
This removes some very old vestigial code that really should have been
removed during the content addressability transition. It implements
something called "reference" but it behaves differently from the actual
reference package. This was only used by client-side content trust code,
and is relatively easy to extricate.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>