Make default addresses on address book page better themable

On the address book page it's currently hard to individually theme the default billing address and the default shipping address as they have the same classes. This can be fixed by giving each default type an extra class.

This was originally mentioned by miccelito in #1666746: Possible to make Extra order information pane (from 'Extra Fields Checkout Pane') appear in user's address book? (top of the issue).

A fix for both 6.x-2.x and 7.x-1.x will come shortly. The default billing address will additionally get the css class 'default-billing-address' and the default shipping address will additionally get the css class 'default-shipping-address'.

This may be a short time fix, as a redesign of the address book is planned after Views integration has been implemented. See #1433034: Redesign the address book page using Views.