Support for adding custom labels to ServiceMonitor

[suyash-811]

Hi,
We are currently trying to set-up Tempo Monolithic as our tracing backend. We would like to scrape metrics from the tempo instance using a serviceMonitor CR. We enabled the serviceMonitor by setting .spec.observability.metrics.serviceMonitors.enabled==true in the CRD.

While the serviceMonitor is successfully created, there is no way to add custom labels to it. Adding such labels would help to select a desired serviceMonitor based on the label.

Is it possible to have this functionality? Maybe an extra configuration block in the CRD to add extra labels to the serviceMonitor CR?
Or the serviceMonitor could also copy all labels from the tempo monolithic / stack instance.

Looking forward to some discussion on this 😄