Add shipping page

[mivano]

Make sure we have a shipping page which performs a call to an external system that list the different shipping methods. Render these to the screen. Implement the code that handles an unavailable shipping service as well (so fallback).

[madkoo]

@mivano Should this happen in the checkout view? What is this external system that the call should be made?

[madkoo]

@rajbos any input maybe from you on this ?