CHIP-0018: KYC-VC Proof Structure

[danieljperry]

• Assign CHIP-18
• Update status to Draft

[danieljperry]

This CHIP is now a Draft. It provides a standard for formatting metadata proofs specifically for Know Your Customer Verifiable Credentials on Chia's blockchain. Feel free to discuss it either on Discord or in our developers' forum:
https://developers.chia.net/t/chip-0018-kyc-vc-proof-structure

Please leave your formal reviews in this PR.

[forReason]

• Instead of strings like "over_18": "true", consider using boolean values like "over_18": true or "over_18":1
• dates such as "issuanceDate": "2023-01-01T12:00:00Z", might be of type ulong, unix timestamp to fall in line with existing routes of the rpc interface
• Ensure that sensitive personal data isn't stored on-chain or in any public platform. Instead, leverage cryptographic proofs or zero-knowledge proofs for verification without revealing the actual data.

[danieljperry]

• Instead of strings like "over_18": "true", consider using boolean values like "over_18": true or "over_18":1

• dates such as "issuanceDate": "2023-01-01T12:00:00Z", might be of type ulong, unix timestamp to fall in line with existing routes of the rpc interface

One of the key features of this CHIP is that it will remain conformant with the W3C specification for Verifiable Credentials. With this in mind, the values for off-chain metadata fields such as dates must be strings. For example, see the details of the issuanceDate property in the W3C spec: https://www.w3.org/TR/vc-data-model/#issuance-date