Environment should be initialized in postsale and not Order::checkout
Create a new order record every time the user clicks on „checkout“
Order object is passed to IsotopePayment::checkoutForm
Added docblock
Use order data instead of cart/config
Use module instance to generate frontend URL
The checkout/step/complete always requires order UID in the URL
added method to find siblings of a TypeAgent
Order object is passed to IsotopePayment::processPayment
Timeout handling is only used in postsale parent class
Updated checkout module to always require UID in URL for step/complete
Updated Order::checkout, the order items are already available