## Issue Addressed
NA
## Proposed Changes
- Adds a HTTP server to the VC which provides Prometheus metrics.
- Moves the health metrics into the `lighthouse_metrics` crate so it can be shared between BN/VC.
- Sprinkle some metrics around the VC.
- Update the book to indicate that we now have VC metrics.
- Shifts the "waiting for genesis" logic later in the `ProductionValidatorClient::new_from_cli`
- This is worth attention during the review.
## Additional Info
- ~~`clippy` has some new lints that are failing. I'll deal with that in another PR.~~