Prometheus discovery endpoint (for SNMP exporter)

[JensErat]

For connecting SNMP exporter, it would be nice to have device autodiscovery in Prometheus. Given we already have all device data read and available, would you accept a pull requests adding a Prometheus SD config endpoint enumerating discovered devices? Probably also helpful for blackbox probing and other stuff.

https://prometheus.io/docs/prometheus/latest/http_sd/

Seems pretty straight forward to me, populate the device data with IPs (and probably some labels) into a TargetGroup and expose the result from https://github.com/prometheus/prometheus/blob/main/discovery/targetgroup/targetgroup.go#L24 as API endpoint.

I do not see a way to configure or read per-device SNMP, so no reason to expose anything with this regard.