Map worker ids to proper URLs

The frontend should transform:

• scheduler_task_id to the link to luigi graph or the entry from the task history (see discussions in lhcb-core/nightly-builds/lb-nightly-scheduler!13 (merged))
• worker_task_id to the URL of the log file and elasticsearch query (see discussions in lhcb-core/nightly-builds/lb-nightly-db!14 (merged))