Enable IWA standard-based metadata for CET and other tokens

[anvabr]

Problem description

Describe the current state of affairs and why it needs to change.

Requirements

For minted tokens create HIP-405 documents containing the relevant metadata as per the emerging IWA VEM standards, specifically the following:

• Unique identifier (Id): An identifier that is assigned when issued.
• Issuer: The Id for the issuing standard registry.
• Core Carbon Principles (CCP): A set of properties that every CCP will have.
• Core Carbon Attributes (CCA): A set of properties where the values can differ significantly between CCPs and allows comparisons and grouping of like CCPs together.

Core Carbon Principles contain:

• AssetId: The serial number or unique identifier of the referenced credit on the standard registry that the token represents.
• Issuance Date: The date of creation.
• Determined Value: Ex-ante, Ex-post
• Verification Standard: VCS, GS, etc.
• Additionality: TBD
• Leakage: TBD
• Reference to Project/MBP/Claim
• Reference to Contract/VerifiedClaims/Claim
• Date Range: The verified period of the benefit claim.

Core Carbon Attributes contain:

• Classification:
  • Category: Reduction, Avoidance or Removal
  • Method: Nature or Technology
  • Vintage
• Storage
  • Biosphere
  • Geosphere
• Durability: permanence risk, near term (up to 20 years), short term (20-50 years), medium term (50-80 years), long term (80-100 years), and very long term (100-1000 years)
• Clear Removals:
  • N2O:≤0
  • CH4:≤0
• Co-benefits: One or more options from a list of the added benefits we get above and beyond the direct benefits of a more stable climate.
• PA-Compliance:
  • Corresponding Adjustment

Definition of done

• Guardian token minting process includes the creation of the HIP-405 compliant JSON metadata based on the VCs/VPs and other data recorded by Guardian for the project/policy.
• Demo policies contain examples of such data
• Documentation is updated

Acceptance criteria

• A customisable and extendable set of attributes can be specified to be included in the HIP-405 compliant JSON metadata document for minting of the tokens.
• Policy authors can specify project requirements for the metadata Voluntary_Ecological_Markets_Overview_Revised.pdf

[paulmadsenhbar]

a challenge is that HIP-405 proposes using the memo field on the token to point at JSON metadata, but I believe? Guardian is already populating the memo?