Find an easy way to remove a specific runner which is used in a few projects
Original title: Show specific runners are coming from which projects
For now if we want to remove a specific runner, we could only do that from the original project which added it. However, we won't know which project it is unless we're going through all of them. This would be very tedious.
If we show which specific runners are belonging to which projects and link to them, this would be much easier to remove a specific runner.
This was discussed in Slack ci channel and brought up again in: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/39#note_12228757
/cc @tmaczukin @pvorb