Improve ontology documentation

[MdechampG]

Purpose

As a OKP4 builder, I would like to have a comprehensive documentation of the ontology, so that I can easily understand the concepts, relationships, and properties defined in the ontology. This documentation is commited in the project.

The generated documentation is aggregated in the OKP4 docusaurus documentation site.

Now that we have a basis of documentation, it would be good to make it more user-friendly.

Todo

• [x] Make 1 page by VC schema
• [ ] Classify the VCs schemas:

Datasets VCs:

• Dataset description credential
• Governance description credential

Digital services VCs:

• Digital service description credential
• Digital service execution order credential
• Digital service execution result credential
• Governance description credential

Zones VCs:

• Zone description credential
• Governance description credential

• [x] Add properties
• [x] Add examples
• [ ] Add thesaurus