Use Download URL of Distribution Management

Currently we try to derive the artifact repository URL from the release or snapshot repository of the distribution management of the POM. But the information we should use is the download URL.

downloadUrl: is the url of the repository from whence another POM may point to in order to grab this POM's artifact. In the simplest terms, we told the POM how to upload it (through repository/url), but from where can the public download it? This element answers that question.