The fixed STS radio IDs are enumerated in the alertsActor STS.yaml file. That does not have all the fields which STS needs, and will become unwieldy with more cryostats: we want to change the way this is done.

The main idea is to assign 100 STS IDs to each cryostat and SM, and to put those in a new stsOffset actorkeys dictionary field. Then from that generate STS.yaml for all the cryostats, where the individual items contain all the fields the alertsActor and the STS needs: (mhsKeywordName, mhsKeywordIdx, stsRadioID, stsDatatype, stsDescription).

Two sub tickets: for adding the stsOffset actorKeys slot, and for reading actorKeys and generating the STS.yaml file.