Change the structure of object reference for the json logger

[LeoDefossez]

The issue is with how object references are currently logged, meaning StringReference, ArrayReference, and ClassReference

For example, for an array reference, the current JSON structure looks like this:

"reference": {
            "type": "java.lang.String[]",
            "uniqueId": 72,
            "refered": {
              "elements": []
            }
}

• reference being an object reference
• refered can be :
  • the fields of a class reference
  • elements of an array reference
  • value of the String reference
    This design makes it hard to quickly understand what kind of object we’re dealing with.

Proposal 1: Flatten the structure
Instead of having a generic "reference" object with a "refered" field, we can directly log the specific type of reference.
Example for an array:

"ArrayReference":{
             "type": "java.lang.String[]",
            "uniqueId": 72,
            "elements": []
}

This way, there’s no extra “wrapper” for all ObjectReference types.

Proposal 2: Keep a wrapper but be explicit
If we still want a generic ObjectReference container, we can make the type explicit inside it:

"ObjectReference":{ 
    "type": "java.lang.String[]",
    "uniqueId": 72,
    "ArrayReference":{
            "elements": []
      }
}

This option could be helpfull for the importer for FamixCallStack, but is less space efficient for the outputted file