[fedora-review] Consider packages installed with XMVn in _is_xmvn_pkg

This gets rid of false positives for jpackage-utils requires test and old style
packaging tests.
[fedora-review] Recommend .mfiles instead of %{_mavenpomdir}

Using %add_maven_depmap with .mfiles is the only supported way.
[fedora-review] Update link anchors
[fedora-review] Replace mvn-rpmbuild check

Replace checking for local depmap used with mvn-rpmbuild with checking for
using mvn-rpmbuild itself. It's been deprecated for a long time, we should warn
about it.
[fedora-review] Note about optional javadocs