Add ERC: Structured Data Clear Signing Format

[lcastillo-ledger]

This is Ledger's proposal for a format enabling smartcontract developers to define the intended UI on wallets when signing a transaction or an EIP 712 message intended for the contract.

For more context, you can refer to this video: https://www.youtube.com/watch?v=-O7aX6vUvs8

[eip-review-bot]

File ERCS/erc-7730.md

Requires 1 more reviewers from @g11tech, @SamWilsn, @xinbenlv

[usame-algan]

Is it in the scope of this EIP on how to handle off-chain data? e.g. some swap transactions merely contain a reference (orderId) to the actual data. So an intent that is purely based on the transaction data might not give the user enough information whereas if the dApp knew what to do with the orderId, more information like the amount or tokens involved in the swap could be displayed.

[lcastillo-ledger]

I updated to take all reviewers comments into account and pass the linter checks

[SamWilsn]

Your specification section has parts that begins with "This specification supports..." or "This specification uses...". That phrasing is a little odd. Instead simply describe what requirements implementations have to meet.

[github-actions]

The commit b2836af (as a parent of 8544e22) contains errors.
Please inspect the Run Summary for details.