Evented Sämubox

[hairmare]

Nowplaying should receive "Sämubox" style information via event api rather than polling https://github.com/radiorabe/virtual_saemubox.

• implement receiving updates via /webhook api from feat: evented track input #140
  • ended up not being useful so far, might remove before v3
• explore if pathfinder can send RaBe CloudEvents on it's own to get rid of virtual-saemubox (it cant: Evented Sämubox #141 (comment))
  • the RestApi feature is available in Pathfinder 1.8 which we have yet to upgrade to. this will be investigated once the upgrade has been completed but the docs indicate it might be useable
  • converting pathfinder events to RaBe CloudEvents happens here: https://github.com/radiorabe/pathfinder-cloudevents-service
• implement receiving cloudevents from pathfinder instead of /webhook api
• Rabe CloudEvents Output virtual-saemubox#62
• drop saemubox_id int alltogether (v3)

[hairmare]

explore if pathfinder can send RaBe CloudEvents on it's own to get rid of virtual-saemubox

the RestApi feature isn't quite op to par to send JSON events of any kind since it's templating seems to heavily rely on { and } without providing an obvious way to generate JSON. All examples i could find seem to be XML centric but look and feel like they only support a tiny sbuset of actual XML.

As such, if we start using the RestApi, we would still have to have some component that ingests Pathfinder events and transforms them into forwardeable CloudEvents.

This indicates that we will most likely want to keep the virtualsaemubox component and teach that how to send cloud events. refactoring that to the native RestApi probably doesn't add enough value, but we would finally want to implement a more stable virtual-saemubox that can reconnect when Pathfinder goes awol.