Updated to work against latest Nexus (2.5.1-01)

This includes [nikolavp](https://github.com/nikolavp)'s [changes to properly populate package fields](https://github.com/Raniz85/nexus-apt-plugin/commit/20b664920f7391c3458458adfeb708c44579abb2).

pom.xml is completely rewritten and now includes the nexus-plugin-bundle-maven-plugin for packaging and compiles against nexus 2.5.1-01 which is currently the latest version.

It also includes a workaround that works despite [NEXUS-5799](https://issues.sonatype.org/browse/NEXUS-5799), which means that we can't depend on the min index creator since it is possible for the debian-package index creator to be run before it, causing updateArtifactInfo not to do anything.