feat: exec hooks

[loocapro]

Motivation

Add before/after execution hooks to BlockExecutor, with no-op defaults and minimal overhead:

• Zero-cost abstraction: Hooks default to no-op, so callers pay nothing when they don’t use them.
• Simple API: Use .before(|evm, tx| ...) and .after(|evm, result| ...) to add hooks.

Solution

Added a new before and after trait method for BlockExecutor in order to set custom behaviour. New API:

 let executor = factory.create_executor(evm, ctx);

 let gas_used = executor
     .before(|evm, tx| { Ok(()) })
     .after(|evm, result| { Ok(()) })
     .execute_transaction(&recovered_tx)?;

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes