Block processing detailed metrics

Add more detailed metrics for block processing. 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_processing_requests_total`: Count of blocks submitted for processing
- [ ] `beacon_block_processing_successes_total`: Count of blocks processed without error
- [ ] `beacon_block_processing_seconds`: Full runtime of block processing
- [ ] `beacon_block_processing_block_root_seconds`: Time spent calculating the block root when processing a block.
- [ ] `beacon_block_processing_db_read_seconds`: Time spent loading block and state from DB for block processing
- [ ] `beacon_block_processing_catch_up_state_seconds`: Time spent skipping slots on a state before processing a block.
- [ ] `beacon_block_processing_committee_building_seconds`: Time spent building/obtaining committees for block processing.
- [ ] `beacon_block_processing_signature_seconds`: Time spent doing signature verification for a block.
- [ ] `beacon_block_processing_core_seconds`: Time spent doing the core per_block_processing state processing.
- [ ] `beacon_block_processing_state_root_seconds`: Time spent calculating the state root when processing a block.
- [ ] `beacon_block_processing_db_write_seconds`: Time spent writing a newly processed block and state to DB
- [ ] `beacon_block_processing_attestation_observation_seconds`: Time spent hashing and remembering all the attestations in the block