feat: use execute_from_outside (SNIP-9) to broadcast eth tx

[Eikix]

Why

We currently rely on the __validate__ & __execute__ semantic from Starknet to broadcast eth transaction. This brings the following limitations

• the step limit of __validate__ is lower than the one of __execute__ and not sufficient for some large tx
• we cannot do the full eth validation in __validate__ because we can't access the balance of the account
• since some validation is also done in __execute__, we face a nonce mismatch error in some edge cases
• we had to add some storage var for the library calls in the account contract
• if tx fees are not deactivated for Kakarot accounts, the accounts may face a tx reverted for unsufficient (starknet) funds while it was supposed to be good from the eth point of view

What

Using the SNIP 9 execute_from_outside standard, we can move all the required validation to a real "execute" entrypoint, call whatever contract is required, and have a proper nonce management not conflicting with the Starknet one.

How

Tasks

Preview Give feedback

1. Do a minimal PoC to benchmark __validate__ step limits required for tx up to 130kb of data
2. If the limit is significantly lower than the current ~50step/byte, move forward !