Add createdAt custom field to Payone notifications

[andrii-kovalenko-ct]

Now the notifications are stored like this:

"fields": {
            "timestamp": "2017-03-20T15:25:32Z",
            "txAction": "paid",
            "sequenceNumber": "0",
            "notification": "Notification{accessid='null', productid='null', price='53.95', sequencenumber='0', reference='814910', txid='219140063', country='DE', userid='98411182', currency='EUR', txtime='1490023532', clearingtype='vor', mode='live', transactionStatus=null, txaction=PAID}"
          }

where timestamp is a Date reflection of txtime Unix timestamp. But the txtime is just a time where the initial transaction had been created (Initiating payment process (Unix timestamp))

To follow and investigate notifications lifecycle we should store the notification receive time, so:

• Expand PAYONE_INTERACTION_NOTIFICATION CTP Type - add new field like:

    {
        "name": "createdAt",
        "label": {
            "en": "createdAt"
        },
        "required": true,
        "type": {
            "name": "DateTime"
         },
         "inputHint": "SingleLine"
     }