Creates a webhook for the given merchant.post https://api-sandbox.nofrixion.com/api/v1/webhooksCallbacksPayoutposthttps://your.server.com/nofrixion/webhookPaymentRequestposthttps://your.server.com/nofrixion/webhookReportposthttps://your.server.com/nofrixion/webhookRuleposthttps://your.server.com/nofrixion/webhookTransactionPayinposthttps://your.server.com/nofrixion/webhookTransactionPayoutposthttps://your.server.com/nofrixion/webhookPayrunposthttps://your.server.com/nofrixion/webhook