Saturation monitor addon with own output channel

As suggested in comment on !103 (closed), I think keeping 10 Hz saturation monitoring updates on an output channel preferable. It can, however, be a different output channel than the one for fast data such that it can bind to different interface. I had to update the interface between correction device and addons a bit for this:

• Addon needs to know its prefix in the schema
  • It used to only be passed to extend_device_schema (where we can add an OUTPUT_CHANNEL)
  • To actually writeChannel at runtime, we need to know the full name of the channel
• Addon needs to know train ID per input such that matching works
• Could extract from hash (and initially did), but that's cumbersome - and breaks in my testing environment where timeserver is made up, but replayed data has actual train IDs

requested review from @amunnich

assigned to @hammerd

marked this merge request as ready

merged

mentioned in commit 71b6c6d0

I did not fully understand the changes to the SaturationWarningAggregator, but the rest made sense. Thx for taking care.

No problem. The changes to the aggregator are mostly just reusing code to provide the device schema; it's essentially the same node as in the output schema for the output channels. Do you know when we should test this? I can deploy whenever it suits instruments, though am on vacation next week, limiting support.

I do not know about testing. Maybe best to announce the prepared solution here and ask: https://redmine.xfel.eu/issues/160688