Webhooks

[samdark]

Requests are usually coming in the form of webhooks when certain actions are done.

We need:

1. Common means for incoming request validation. Each provider does the validation differently.
2. Processing of incoming data and returning common objects.

Should be something like:

WebHookInterface
{
    public function isValid(): bool;
    public function getPayment(): ?Payment;
    public function getRefund(): ?Refund;
    public function getSubscription(): ?Subscription;
    // ...
}