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" />

beacon_node/beacon_chain/src/data_column_verification.rs

@@ -15,7 +15,7 @@ use ssz_derive::{Decode, Encode};
 use std::iter;
 use std::marker::PhantomData;
 use std::sync::Arc;
-use tracing::debug;
+use tracing::{debug, instrument};
 use types::data_column_sidecar::ColumnIndex;
 use types::{
     BeaconStateError, ChainSpec, DataColumnSidecar, DataColumnSubnetId, EthSpec, Hash256,
@@ -412,6 +412,7 @@ impl<E: EthSpec> KzgVerifiedCustodyDataColumn<E> {
 /// Complete kzg verification for a `DataColumnSidecar`.
 ///
 /// Returns an error if the kzg verification check fails.
+#[instrument(skip_all, level = "debug")]
 pub fn verify_kzg_for_data_column<E: EthSpec>(
     data_column: Arc<DataColumnSidecar<E>>,
     kzg: &Kzg,
@@ -426,6 +427,7 @@ pub fn verify_kzg_for_data_column<E: EthSpec>(
 ///
 /// Note: This function should be preferred over calling `verify_kzg_for_data_column`
 /// in a loop since this function kzg verifies a list of data columns more efficiently.
+#[instrument(skip_all, level = "debug")]
 pub fn verify_kzg_for_data_column_list<'a, E: EthSpec, I>(
     data_column_iter: I,
     kzg: &'a Kzg,
@@ -470,6 +472,7 @@ where
     Err(errors)
 }
 
+#[instrument(skip_all, level = "debug")]
 pub fn validate_data_column_sidecar_for_gossip<T: BeaconChainTypes, O: ObservationStrategy>(
     data_column: Arc<DataColumnSidecar<T::EthSpec>>,
     subnet: DataColumnSubnetId,