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_slot_processing.rs

@@ -4,6 +4,7 @@ use crate::upgrade::{
 };
 use crate::{per_epoch_processing::EpochProcessingSummary, *};
 use safe_arith::{ArithError, SafeArith};
+use tracing::instrument;
 use types::*;
 
 #[derive(Debug, PartialEq)]
@@ -25,6 +26,7 @@ impl From<ArithError> for Error {
 /// If the root of the supplied `state` is known, then it can be passed as `state_root`. If
 /// `state_root` is `None`, the root of `state` will be computed using a cached tree hash.
 /// Providing the `state_root` makes this function several orders of magnitude faster.
+#[instrument(skip_all)]
 pub fn per_slot_processing<E: EthSpec>(
     state: &mut BeaconState<E>,
     state_root: Option<Hash256>,
@@ -85,6 +87,7 @@ pub fn per_slot_processing<E: EthSpec>(
     Ok(summary)
 }
 
+#[instrument(skip_all)]
 fn cache_state<E: EthSpec>(
     state: &mut BeaconState<E>,
     state_root: Option<Hash256>,