This will create a new product along with a new Sku for the defaultSku, along with new
Skus for all of the additional Skus. This is achieved by simply detaching the entities
from the persistent session, resetting the primary keys and then saving the entity.
Note: Media for the product is not saved separately, meaning if you make a change to the
original product's media items (the one specified by productId) it will change the
cloned product's media and vice-versa.