feat(telemetry): register metrics via callback

[SuperFluffy]

Summary

Register metrics for a service through a callback on the telemetry builder.

Background

astria_telemetry::Config should be the central entry point to configure telemetry and metrics. Before this patch the metrics provider, buckets, and global labels were set through config, but actual metrics specific outside of it. With this patch this is done in one step.

Changes

• add Config::register_metrics on telemetry builder
• change all services to pass their initialization function to it.

Testing

Must be observed in a dev cluster.