OpenAPI Support preview

From Keycloak documentation:

The OpenAPI definitions are a feature that is currently in preview. Please provide your feedback by joining this discussion while we’re continuing to work on this. If you find something is outdated or wrong, create a GitHub issue and provide a pull request.

It means we can use OpenAPI definitions to generate full-fledged API.

• https://www.keycloak.org/docs-api/latest/rest-api/
• https://www.keycloak.org/docs-api/latest/rest-api/openapi.json
• https://www.keycloak.org/docs/latest/release_notes/