Document Beyla integration with OTEL collectors and prometheus scrapers

[mariomac]

• When Beyla exports OTEL data to an OTEL collector or Alloy, we should document that honor_labels is required to avoid the collector overriding the instance ID as provided by Beyla. Beyla provides an instance ID per monitored process, but the collector would override it by a common Beyla instance ID.

• Check if something is needed when exporting the data via Prometheus, such as making sure that instance is the service_instance_id field.

[grafsean]

@mariomac following up on older issues, is this still relevant?

[cforce]

Also its unclear where in a beyla-config.yml someone shall set this honor_labels

[marctc]

@cforce that option needs to be see in the scrape config of Prometheus not in Beyla,

@grafsean yes, refer to previous comment, as still is a source of confusion often (me included).