Include shipment costs

[arkaitzgarro]

In most of the projects, when the items are shipped to the client, we need to know the costs of this shipment.

I've seen than @mmoreram and @alch are working in a shipping component, but it seems that is not included into the order yet. Are you ok if we include a shipping cost method into PaymentBridge?

/**
 * Get shipping amount
 *
 * @return integer
 */
 public function getShippingAmount() {
     // Calculate the costs for this order
     // 0 if it is free
 }

And then create the form field if applicable:

/*
 * PaymentBridge stores shipping amount in cents
 */
$shippingAmount = $this
        ->paymentBridge
        ->getShippingAmount();

if ($shippingAmount > 0) {
    $formBuilder
        ->add('shipping_1', 'hidden', array(
            'data' => $shippingAmount,
        ))
    ;
}