Centralize artifacts

Centralize artifacts

Rather than having three different sets of artifacts:
- mdsal-artifacts
- config-artifacts
- benchmark-artifacts

Create a project-wide controller-artifacts, just as the guidelines
tell us to. This has the benefit for downstreams, as they do not
need to track multiple versions. It also benefits us, as we have
a single place for tracking what we produce.

Change-Id: I73cc02c6f1df6c4d705ef83dfc57e6aad17c6287
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>