Adds support for post-quantum ML-DSA & ML-KEM algorithms

[prabhu]

Fixes #674

With inspiration from the Node.js PRs and this, this pull request adds three new post-quantum algorithms: "ML-DSA-44", "ML-DSA-65", and "ML-DSA-87" and three new key encapsulation mechanisms: "ML-KEM-512", "ML-KEM-768", "ML-KEM-1024" to better future-proof BOM signature validity. The hypothetical but real threat this addresses is that traditional signatures with RSA/ECDSA may become invalid when quantum computers break them.

Following alternative ideas could be considered:

1. URI-Based references

"algorithm": "urn:nist.gov:fips204:ml-dsa-44" instead of simple upper case enum strings. This however is a significant breaking change to replace all existing identifiers in use.

2. Extend signer definition

Signature object support signer as one of the types. A new type called postQuantumSigner could be created to extend signer to capture additional attributes related to PQ algorithms and also to support a broad range of PQ algorithms.

"properties": {
            "signers": {
              "type": "array",
              "title": "Signature",
              "description": "Unique top level property for Multiple Signatures. (multisignature)",
              "items": {"$ref": "#/definitions/signer"}
            }
          }

3. Enable additional properties

Currently, additional properties are disabled for signer. To increase flexibility, this could be enabled.

This PR proposes a simple enhancement to the enum, key type indicators, and validation, making this feature >= 1.7 only without any possibility for backports.

TBD:

Enhancing CBOM to support the corresponding OID values.

Algorithm	OID
ml-dsa-44	2.16.840.1.101.3.4.3.17
ml-dsa-65	2.16.840.1.101.3.4.3.18
ml-dsa-87	2.16.840.1.101.3.4.3.19
ml-kem-512	2.16.840.1.101.3.4.4.1
ml-kem-768	2.16.840.1.101.3.4.4.2
ml-kem-1024	2.16.840.1.101.3.4.4.3