Add configurations for Ci::RescueStaleLiveTraceWorker

Shinya Maedarequested to merge
add-rescue-stale-live-trace-cron-worker into master

We're going to add a cron worker - Ci::RescueStaleLiveTraceWorker. This worker archive stale live traces in the case BuildFinishedWorker couldn't complete its job by receiving SIGKILL.

The MR is https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18680. This is scheduled in 11.0 as Deliverable.

Here is an issue about how we concluded that this cron worker is needed https://gitlab.com/gitlab-org/gitlab-ce/issues/46097

/cc @ayufan

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