Enable IWA standard-based metadata for CET and other tokens

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

### Requirements
For minted tokens create [HIP-405 ](https://hips.hedera.com/hip/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](https://github.com/hashgraph/guardian/files/9290295/Voluntary_Ecological_Markets_Overview_Revised.pdf)