feat: added payment method - sofort

[Shivam25092001]

ADDED

• Payment method: sofort

TESTING

• Create the payment intent using: (eligible currency: EUR, country: AT (any European country))

  var paymentIntent = await hyper.paymentIntents.create({
    amount: 2999,
    currency: 'EUR',
    billing: {
      address: {
        line1: '1467',
        line2: 'Harrison Street',
        line3: 'Harrison Street',
        city: 'San Fransico',
        state: 'California',
        zip: '94122',
        country: 'AT',
        first_name: 'PiX',
        last_name: "George",
      },
    },
  });