feat: EthHandler trait

[rakita]

This creates one trait with all the logic, and adds transact_main, transact_main_commit, inspect_main and inspect_main_commit functions that require only Context.

[codspeed-hq]

CodSpeed Performance Report

Merging #2001 will improve performances by 2.88%

_{Comparing rakita/eth_handler_trait (2c91bba) with main (25512fd)}

Summary

⚡ 1 improvements
✅ 7 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	rakita/eth_handler_trait	Change
⚡	transfer	31 µs	30.1 µs	+2.88%