Return full validation failure message if new schema fails validation

[alexanderdean]

Not just an error message, but the full JSON Schema validation failure.

[BenFradet]

Pretty much done except for pretty printing.

[BenFradet]

This is done, in case of a failed validation the api will return the following json:

{
  "status": 400,
  "message": "The json provided is not a valid self-describing json",
  "report": {
        "level": "error",
        "schema": {
            "loadingURI": "#",
            "pointer": ""
        },
        "instance": {
            "pointer": ""
        },
        "domain": "validation",
        "keyword": "allOf",
        "message": "instance failed to match all required schemas (matched only 1 out of 2)",
        "matched": 1,
        "nrSchemas": 2,
        "reports": {
            "/allOf/0": [
                {
                    "level": "error",
                    "schema": {
                        "loadingURI": "#",
                        "pointer": "/allOf/0"
                    },
                    "instance": {
                        "pointer": ""
                    },
                    "domain": "validation",
                    "keyword": "required",
                    "message": "object has missing required properties ([\"self\"])",
                    "required": [
                        "self"
                    ],
                    "missing": [
                        "self"
                    ]
                }
            ],
            "/allOf/1": []
        }
    }
}

for example, the point is the full report will come along.

[alexanderdean]

Great work Ben!

[BenFradet]

Done in r2, closing.