Support G7 SBOM for AI minimum elements

[bact]

We can use this Software Bill of Materials (SBOM) for Artificial Intelligence - Minimum Elements
https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/KI/SBOM-for-AI_minimum-elements.html
as a guide during generation and warns user that which minimum fields are missing.

Possible to use https://github.com/spdx/ntia-conformance-checker instead of implementing the checker here.

[bact]

The class AiModelMetadata should be extended and at least able to capture all minimum elements in the G7 AI SBOM Minimum Elements https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/KI/SBOM-for-AI_minimum-elements.html listed above.

The class DocumentModel itself or the aggregation of its component should at least able to capture all minimum elements in 2021 NTIA SBOM Minimum Elements https://www.ntia.gov/report/2021/minimum-elements-software-bill-materials-sbom and 2025 CISA SBOM Minimum Elements https://www.cisa.gov/resources-tools/resources/2025-minimum-elements-software-bill-materials-sbom