Add Docusaurus JSON Schema Plugin

[jy95]

• Compliant with OpenAPI 3.1
• Support multiple versions of JSON Schema ( https://www.openapis.org/blog/2021/02/16/migrating-from-openapi-3-0-to-3-1-0 - "$schema now allowed" ) : Draft-07 / Draft 2019-09 / Draft 2020-12