Creates a Company/Payment/PayFac Webhook using the url defined in the request body. It is important to save the secret returned in the response body. All requests made to webhook URLs from ZTLment will contain the ZTLment-Signature header that can be used to verify that the request comes from ZTLment. If the secret_key is used to encrypt the payment_object_id+state and it matches the ZTLment-Signature header you can be sure the request has come from ZTLment.