title: Add public upstream source to azure feed
body: <p>We would like to have</p>
  <pre><code>https://repository.jboss.org/nexus/content/repositories/public/ 
  </code></pre>
  <p>as an upstream sources for our org level azure artifact feed. As far as I understand we can only have public upstream sources from npm, nuget, maven and pypi.</p>
  <p>Can anyone give any leads on how should we go about it.</p>