MSHADE-139: Change the default output file name so that it does not replace the ordinary jar
o Begin to set up modello support for a nice XML spec of the artifact produced by shade.


git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/branches/maven-shade-plugin-3@1437378 13f79535-47bb-0310-9956-ffa450edef68