Improve insert/delete API response

[richard-epsilla]

POST http://localhost:8888/api/MyDB/data/insert -d ...
Response:

{
    "message": "Insert data to MyTable1292 successfully.",
    "result": {
        "inserted": 5,
        "skipped": 3
    },
    "statusCode": 200
}

POST http://localhost:8888/api/MyDB/data/delete -d ...
Response:

{
    "message": "Delete data from MyTable12 successfully.",
    "result": {
        "deleted": 14
    },
    "statusCode": 200
}