Update the spinner component

Overview

When a diff or the builds page loads in a MR, you see this little spinner. It needs improvement.

Proposal

We should update the relevant component in https://design.gitlab.com/components/spinner / gitlab-ui with the pattern library issue's solution in gitlab-design#183 (closed).

Could most likely re-use the dev work in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/12093/diffs to kick things off.

Reference

https://gitlab.com/gitlab-org/gitlab-ce/issues/20084#note_31960795