Pull dependencies from pom.xml or nexus when uploading jar

[FroMage]

Maven deps can come from a pom.xml file next to the imported jar, but apparently all jars generated by Maven have a META-INF/pom.xml file in there that we could use. Alternatively we could use Nexus's web services to do a lookup for the jar's SHA1. That's what the jboss tools team does.