Generate distribution package with only relevant files

Hello,

I added maven-assembly-plugin to the build which packages only relevant files in tar.gz and zip archives. I created a test release with example packages in my fork: https://github.com/pbzdyl/jHiccup/releases/tag/v1.3.9-alpha-1

When drafting that release I just uploaded those two files (*-dist.tar.gz and *-dist.zip). Github generates two more packages with sources.