Optimize importer-offline (batch writing + more parallelism)

[marcospb19-cw]

This PR divides importer-offline's task block-importer into block-executor and block-saver, to separate EVM and storage writing, now both can run in parallel

Besides that, this enabled our RocksDB storage to perform block writes in batches, as a consequence, this leaves execution time as the new bottleneck for importer-offline, which hints that we don't need to optimize the storage further to improve this binary.

[github-actions]

PR Reviewer Guide 🔍

⏱️ Estimated effort to review [1-5]	4
🧪 Relevant tests	No
🔒 Security concerns	No
⚡ Key issues to review	Logging and Monitoring: Ensure that all background tasks such as 'storage-loader', 'block-executor', and 'block-saver' are properly logged and monitored. The current implementation logs errors, but it may benefit from more detailed logging at each significant step, especially given the parallel execution context.
	Error Handling: The use of .unwrap() in run_external_block_executor when sending block_batch to writer_batch_tx could lead to panics if the channel is closed or full. It's recommended to handle this error gracefully.
	Cloning Optimization: In src/eth/primitives/pending_block.rs, the method split_transactions clones each transaction. If possible, consider optimizing to avoid cloning, especially if the transactions are large or this operation is called frequently.
	Tracing Fields: The commented-out spans in StratusStorage methods like read_account and read_slot were removed to potentially optimize performance. If tracing is still required, consider adding lightweight tracing or logging specific, necessary details only.
	Thread Safety and Concurrency: The use of synchronous channels (mpsc::sync_channel) and their interaction in a multi-threaded environment should be carefully reviewed to ensure there are no deadlocks or excessive blocking, especially since the channel capacities are quite small.

[github-actions]

Failed to generate code suggestions for PR

[marcospb19-cw]

Auto-review requested changes: update these comments and quickly check if it's obvious why it behaves this way.

[marcospb19-cw]

Recent smaller changes achieved enough speed improvements in importer-offline, it's unclear now if we need to further improve it or not, closing for now.