[Repository Explorer] Provide a way to copy the artifact URL

[laeubi]

Assume the following use case:

1. I have an URL and put it into the Repo Explorer
2. Now I activate Advanced Mode and select to display bundles
3. I find a bundle I need to further investigate but its is only metadata

It would be useful to have (e.g. on right click) a new Menu Item for each artifact that list if an item has any attached P2 artifact. this looks like this for example:

  <artifacts size='1'>
    <artifact classifier='osgi.bundle' id='org.eclipse.wst.xml.core' version='1.2.800.v202308210520'/>
  </artifacts>

then in this new Menu there could be an entry Copy location of org.eclipse.wst.xml.core 1.2.800.v202308210520 (osgi.bundle) (and if there are more artifacts of course more items) that goes to the Artifact Repo and query for the final URI of that artifact, this then might be a local file or URL.