Multi-arch Support for Registry CI

[Jdubrick]

Which area is this issue related to?

/area ci
/area registry

Issue Description

As part of our CI we are using the .ci/Dockerfile from devfile registry to build an image used for testing here. This Dockerfile and its offline version, .ci/Dockerfile.offline are using amd64 dependencies as part of the build process, this results in the end image being tagged for amd64 in most cases, even when you explicitly try to build for arm64.

Our goal is to move the OpenShift CI using this image to an arm64 instance and as such will need to build and use arm64 images. The noted Dockerfiles above will need to be altered to support building for both amd64 and arm64. A possible solution is to use a tagging system for both architectures and they have separate Dockerfiles. E.g. Dockerfile.amd64, Dockerfile.arm64. The downside of this is we will need to maintain multiple Dockerfiles. An alternate solution is preferred if possible. The use of an environment variable to dynamically set the dependency like registry-operator may work.

Acceptance Criteria

• Registry CI images can be built for either arm64 or amd64 architectures

[Jdubrick]

Blocking #1552