DEPL-6248: rules example jetty-plugin

Initially I didn't want any build tool (neither maven nor gradle) but the problem with remote configuration files is that I could not figure out how to retrieve existing entries or add new ones without some kind of a helper that would use overthere. I wrote it in Java. As a consequence I had to compile it. Other community projects were maven based so I picked that one.

I would like to avoid any kind of a build tool in the sample. It should be enough to copy contents into xld folder and that's it.