Add latest / latest-dev API spec deployments

Marco had opened a MR some time ago: submission-api!175 (merged)

With this we would then build latest and latest-dev:

• latest: Always the last released (via git tag) artifact (here: API spec)
• latest-dev: Always the last artifact present on main branch (here: API spec)

I have adapted and merged the MR. This ticket here is for transparency regarding this and the other APIs (Routing-API, Self-Service API)