Release the Maven dependency proxy

🎉 🎉 Yes! MR 141600 is mine, MINE! 🎉 🎉

(I have this 👽 habit of collecting MR round numbers).

☎ Context

We have been working in iteration to build the Maven dependency proxy.

Read more about this in the documentation.

As such, we have been using a feature flag to gate the proxy.

This flag has been globally rolled out and this MR is the feature flag cleanup MR.

🔬 What does this MR do and why?

• Remove all the feature flag checks that we had in the backend. (This will also release the frontend).
  • Clean up the related specs.
• Release the related GraphQL types, queries and mutations. (They are not marked as alpha anymore).
• Update the related documentation.

🏁 MR acceptance checklist

✅

🖼 Screenshots or screen recordings

None

⚙ How to set up and validate locally

Have a project ready and follow https://docs.gitlab.com/ee/user/packages/package_registry/dependency_proxy.

Note that you need a GitLab license, since this is a GitLab Premium feature.