Block production detailed metrics

Add more detailed metrics for block production. From https://github.com/ChainSafe/lodestar/issues/2468

Originally inspired in May 2021 from here
https://github.com/sigp/lighthouse/blob/stable/beacon_node/beacon_chain/src/metrics.rs

- [ ] `beacon_block_production_requests_total`: Count of all block production requests
- [ ] `beacon_block_production_successes_total`: Count of blocks successfully produced
- [ ] `beacon_block_production_seconds`: Full runtime of block production
- [ ] `beacon_block_production_state_load_seconds`: Time taken to load the base state for block production
- [ ] `beacon_block_production_slot_process_seconds`: Time taken to advance the state to the block production slot
- [ ] `beacon_block_production_unaggregated_seconds`: Time taken to import the naive aggregation pool for block production
- [ ] `beacon_block_production_attestation_seconds`: Time taken to pack attestations into a block
- [ ] `beacon_block_production_process_seconds`: Time taken to process the block produced
- [ ] `beacon_block_production_state_root_seconds`: Time taken to calculate the block's state root
- [ ] `beacon_attestation_production_requests_total`: Count of all attestation production requests
- [ ] `beacon_attestation_production_successes_total`: Count of attestations processed without error
- [ ] `beacon_attestation_production_seconds`: Full runtime of attestation production