Improve HTTP API metrics and logs

[michaelsproul]

@macladson and I noticed that we are missing some important routes from the HTTP metrics. This bloc probably needs an update:

lighthouse/beacon_node/http_api/src/lib.rs

Lines 212 to 243 in d60c24e

	// First line covers `POST /v1/beacon/blocks` only
	equals("v1/beacon/blocks")
	.or_else(|| starts_with("v1/validator/blocks"))
	.or_else(|| starts_with("v2/validator/blocks"))
	.or_else(|| starts_with("v1/validator/blinded_blocks"))
	.or_else(|| starts_with("v1/validator/duties/attester"))
	.or_else(|| starts_with("v1/validator/duties/proposer"))
	.or_else(|| starts_with("v1/validator/duties/sync"))
	.or_else(|| starts_with("v1/validator/attestation_data"))
	.or_else(|| starts_with("v1/validator/aggregate_attestation"))
	.or_else(|| starts_with("v2/validator/aggregate_attestation"))
	.or_else(|| starts_with("v1/validator/aggregate_and_proofs"))
	.or_else(|| starts_with("v2/validator/aggregate_and_proofs"))
	.or_else(|| starts_with("v1/validator/sync_committee_contribution"))
	.or_else(|| starts_with("v1/validator/contribution_and_proofs"))
	.or_else(|| starts_with("v1/validator/beacon_committee_subscriptions"))
	.or_else(|| starts_with("v1/validator/sync_committee_subscriptions"))
	.or_else(|| starts_with("v1/beacon/pool/attestations"))
	.or_else(|| starts_with("v2/beacon/pool/attestations"))
	.or_else(|| starts_with("v1/beacon/pool/sync_committees"))
	.or_else(|| starts_with("v1/beacon/blocks/head/root"))
	.or_else(|| starts_with("v1/validator/prepare_beacon_proposer"))
	.or_else(|| starts_with("v1/validator/register_validator"))
	.or_else(|| starts_with("v1/beacon/"))
	.or_else(|| starts_with("v2/beacon/"))
	.or_else(|| starts_with("v1/config/"))
	.or_else(|| starts_with("v1/debug/"))
	.or_else(|| starts_with("v2/debug/"))
	.or_else(|| starts_with("v1/events/"))
	.or_else(|| starts_with("v1/node/"))
	.or_else(|| starts_with("v1/validator/"))
	.unwrap_or("other")

With tracing, we also lost the rather useful log:

lighthouse/beacon_node/http_api/src/lib.rs

Lines 205 to 212 in bf955c7

	debug!(
	log,
	"Processed HTTP API request";
	"elapsed" => format!("{:?}", info.elapsed()),
	"status" => status.to_string(),
	"path" => info.path(),
	"method" => info.method().to_string(),
	);

Improving this will help us see the difference in perf when upgrading from warp to axum

While we're restoring that log, we should ensure it always logs milliseconds as a float like:

elapsed_ms: 1.0

elapsed_ms: 0.001

elapsed_ms: 50000.0

This makes the logs easier to parse/categorise (no units to remove)

[jimmygchen]

Fixed in #7225