Download squirrelsql-update-site-plugin JAR file with all dependencies

This project produces the Mojo that can build a proper release.xml for the SQuirreLSQL update site, given a directory where the updated jar artifacts are located. This plugin accepts a directory in it's configuration and expects to find three sub-directories there : core, plugins and i18n. It then categorizes the artifacts found in those directories accordingly in the final release.xml file, that is generated in the specified folder.