Metrics helpers

Collects a bunch of metrics providers and related features such as Metronome for usage with metrics collections.

This crate also reexports Prometheus metric types which are expected to be implemented by subsystems.

polkadot-node-metrics

Testing

Before running cargo test in this crate, make sure the worker binaries are built first. This can be done with:

cargo build --bin polkadot-execute-worker --bin polkadot-prepare-worker