Prepare Read the Docs to support multiple spec versions #299
Description
Read the Docs currently exposes only the current v0.5 version.
Even if v1.0 is not released yet, we should prepare the documentation setup to support multiple spec versions in parallel once it is published, while keeping backward compatibility with existing versions:
This includes having namespaced, stable URLs (eg. /v0, /v1) so references and links remain reliable over time and maintain the old ones, maybe with a banner + switcher that says it's not the latest version.