We'd like to support json configuration file for jextract. This would help

1. IDE integration
2. to get around the limitations of command line options and args file
3. to be able to check-in configurable files into source repos for reliable jextraction on different machines/sessions.

Towards this, we need a json library to parse/convert & pretty print json and a way convert JSON objects/arrays to java records - so that the rest of the jextract can use strongly typed record for configuration rather JSON library objects.

We can use 'skara' projects 'json' library as a starting point for this preparation.