Ingest GRB candidates from SVOM

The Space Variable Objects Monitor (SVOM) will be hopefully launched in late 2023, making it an attractive mission to add to the RAVEN workflow. This requires the following:

• Create/modify GCN or Kafka listener to ingest events from SVOM
• Modify GCN VOEvent ingestion for new notice type (see computing/gracedb/server#338 (closed))
• Ensure SVOM events can create external events either in their current form or with some wrapper function (i.e. get example GCN notice or equivalent and see if can be uploaded directly)
• Contact GraceDB developers to add pipeline='SVOM' if not already available (see computing/gracedb/server#255 (closed))
• Modify GRB listener if similar enough to current workflow in order to fully include in RAVEN pipeline. Determine every notice type we would like to listen to.
• Determine expected rate (#/year) of additional detected GRBs (i.e. independent of Fermi-GBM, Swift-BAT, INTEGRAL, and AGILE-MCAL) and whether the individual significance (FAR?) of the GRB is available or relevant (e.g. is very high significance so that FAR_FRB << FAR_GW?). Increase rates in ligo-raven if needed (see https://git.ligo.org/lscsoft/raven/-/blob/7561aeb07c1071722d619398b37fc0f563ecd0b7/ligo/raven/search.py#L499)
• Determine how the GRB sky localization could be downloaded from the experiment or created via existing tools in gwcelery
• Add relevant values to RAVEN pipeline (time window, raven.trigger_raven_alert) and add exceptions when different from standard GRB workflow
• Add testing via pytests, internal MDCs, and/or O3 replay to ensure system works as expected

Example of SVOM Eclairs notice: sb23041100_eclairs-wakeup_2.xml