Implement AA mechanism in core

[b1m0n]

Introduction

We are heading to implement a more generic and flexible account abstraction scheme. Accounts in U2U will be able to initiate transactions, like an EOA, but can also have arbitrary logic implemented in them, like a smart contract. The simple AA implementation at PR https://github.com/unicornultrafoundation/go-u2u/pull/64 and https://github.com/unicornultrafoundation/go-u2u/pull/66 is kinda simple, subjects to be spammed because this implementation doesn't have a selective mechanism for paying gas. The arbitrarity in AA logic and other DoS protection can be achieve via this new transaction type and how we treat the execution/gas estimation flow.

References:

• https://docs.zksync.io/build/developer-reference/account-abstraction.html
• https://github.com/matter-labs/zksync-era/blob/main/docs/specs/zk_evm/account_abstraction.md

Checklist

• [x] Define a new transaction type EIP712TxType = 0x71 to implement Transaction interface: https://github.com/unicornultrafoundation/go-u2u/issues/91
• [x] TransactionHelper, IAccount, IPaymaster smart contract interfaces and simple implementations for testing purposes: https://github.com/unicornultrafoundation/go-u2u/issues/94
• [x] Implement the paymaster flow first to serve AA gas sponsoring in the future: https://github.com/unicornultrafoundation/go-u2u/issues/94
• [ ] Apply the EIP712TxType execution and gas estimation flow
  • [ ] Account versioning to allow breaking changes in the future
  • [ ] Nonce ordering to signal to the operator which nonce ordering it should expect
  • [ ] Extending EIP-4337 to provide DoS protection for the operator by imposing several restrictions on the validation step of the account
• [ ] Documentation

[khoau2u]

• [ ] Implement the alternative account flow