Push to both DSD and ECR Docker registries
Push to both DSD and ECR Docker registries

Unfortunately, using the DSD registry forces us to lock everything to
Docker 17.03 where we want to use those images, which is proving to be
a blocker.

In order to remove that constraint, we chose to push the built image
into both Docker registries.

ministryofjustice/cla_public,ministryofjustice/cla_public,ministryofjustice/cla_public,ministryofjustice/cla_public