SLES SMT Server needs replaced

Some time before 6 March 2020, our SLES AWS instance serving as an SMT server (package mirror) for our SLES image builders have disappeared / become unreachable.

Prior to the failure, we've been using a long-cached image, and as a result, apparently missed the problem occuring.

failures:

• 6 March 2020 https://dev.gitlab.org/cookbooks/gitlab-omnibus-builder/pipelines/146289
• 9 Jan 2020 https://dev.gitlab.org/cookbooks/gitlab-omnibus-builder/-/jobs/6331054