BLC-846 - delegate Sku properties to getters if they are null in that particular Sku
BLC-445 - Refactor Sku methods to use bean-style getters
Ensure that the custom persistence handler for Sku is registered as the default (no custom criteria is required). Refactor some of the functionality so that subclasses can continue to customize the returned list of Skus easier. In this way, components that need to provide specific lookup functionality for Skus can still benefit from the product option value displaying in the grid