add reference - delete source not supported (class deleted, child of class added/updated)

Example in DELETE USE:
```js
"2way-a": [
{
"op": "add",
"path": "/package/classes/2/references/0", // path here
"value": {
"containment": false,
"id": "category",
"lowerBound": 1,
"type": {
"$ref": "#/package/classes/1"
},
"upperBound": -1
}
}
],
"2way-b": [
{
"op": "delete",
"path": "/package/classes/2", // path here
"value": {
"id": "Project",
"references": []
}
}
]
```

Example in DELETE UPDATE:
```js
"2way-a": [
{
"op": "add",
"path": "/package/classes/1/attributes/0", // attribute for deleted class was added
"value": {
"id": "SDG",
"upperBound": -1,
"lowerBound": 1,
"type": "int"
}
}
],
"2way-b": [
{
"op": "delete",
"path": "/package/classes/1", // class deleted
"value": {
"id": "Category",
"attributes": []
}
}
]
```

it is not in reference only the paths themself

but the current parent child detection only looks in $ref

add path is contained in delete path