Instrument tracing spans for block processing and import (#7816)

#7815

- removes all existing spans, so some span fields that appear in logs like `service_name` may be lost.
- instruments a few key code paths in the beacon node, starting from **root spans** named below:

* Gossip block and blobs
* `process_gossip_data_column_sidecar`
* `process_gossip_blob`
* `process_gossip_block`
* Rpc block and blobs
* `process_rpc_block`
* `process_rpc_blobs`
* `process_rpc_custody_columns`
* Rpc blocks (range and backfill)
* `process_chain_segment`
* `PendingComponents` lifecycle
* `pending_components`

To test locally:
* Run Grafana and Tempo with https://github.com/sigp/lighthouse-metrics/pull/57
* Run Lighthouse BN with `--telemetry-collector-url http://localhost:4317`

Some captured traces can be found here: https://hackmd.io/@jimmygchen/r1sLOxPPeg

Removing the old spans seem to have reduced the memory usage quite a lot - i think we were using them on long running tasks and too excessively:
<img width="910" height="495" alt="image" src="https://github.com/user-attachments/assets/5208bbe4-53b2-4ead-bc71-0b782c788669" />

consensus/state_processing/src/per_epoch_processing/single_pass.rs

@@ -11,6 +11,7 @@ use itertools::izip;
 use safe_arith::{SafeArith, SafeArithIter};
 use std::cmp::{max, min};
 use std::collections::{BTreeSet, HashMap};
+use tracing::instrument;
 use types::{
     consts::altair::{
         NUM_FLAG_INDICES, PARTICIPATION_FLAG_WEIGHTS, TIMELY_HEAD_FLAG_INDEX,
@@ -134,6 +135,7 @@ impl ValidatorInfo {
     }
 }
 
+#[instrument(skip_all)]
 pub fn process_epoch_single_pass<E: EthSpec>(
     state: &mut BeaconState<E>,
     spec: &ChainSpec,