Restructure project + GitHub actions

[duttonw]

Hi @gagern,

I found your project quite interesting and was looking at doing some improvements. In this PR I've added GitHub actions to run maven and maven is using the frontend-maven-plugin to trigger node and run its parts.

I've also restructured it into a maven java styled structure and moved JavaScript items into their corresponding 'node' folders.

Just wondering, did you ever get around to doing a serializer in node?

Regards

@duttonw