To some extent, yes. I don't think it should be included in the Solr war file though, as it's a separate application.
That's great. We can start by modifying the existing directory structure in the attached archive to the contrib structure following by DIH.
Also there's a dependency on the solr.war for the integration tests.
Can we use the AbstractSolrTestCase or embedded Jetty (see JettyWebappTest) for integration tests instead of relying on solr.war directly? That will simplify the builds.
For example we need to decide what "package" should do. Compiled files only? Source, too? What about documentation - manual, source of manual, javadoc.
These targets should do exactly as (or close to) what is done by Solr's build file. We should be able to create and deploy the war file for this contrib deployed alongside Solr in the example/webapps folder so that no manual steps may be needed to see the interface. Let's get the basic compile, package, test working after which we can focus on javadoc, dist, documentation etc.