eth/catalyst: add initial OpenTelemetry tracing for newPayload

[jrhea]

This PR adds initial OpenTelemetry tracing to the Engine API, focusing on engine_newPayload*.

jsonrpc.engine/newPayloadV4 
|  |- engine.newPayload  [block.number, block.hash, tx.count]
|     |- core.blockchain.InsertBlockWithoutSetHead
|        |- bc.processor.Process
|        |  |- core.ApplyTransactionWithEVM  [tx.hash, tx.index]
|        |  |- core.ApplyTransactionWithEVM  [tx.hash, tx.index]
|        |  |- ...  (one per transaction)
|        |  |- core.postExecution
|        |- bc.validator.ValidateState

[MariusVanDerWijden]

LGTM

[MariusVanDerWijden]

Can we also get a span for the post-block system calls?

[jrhea]

Do you want a span for each one? Would any specific attributes be helpful?

[fjl]

It's OK to have a span for all of them at once. In order to make this work, we should move the system calling into its own method and start a span at top, then end it with defer.

[jwasinger]

@fjl This is the line that breaks blockchain tests. For some reason, it is expected to return a non-nil requests list post-prague if there are no requests.

Seems to do with the hash of a nil requests not matching that of an empty one.