Revert "Added getPrice() to Sku/SkuImpl to resolve Sku price, considering the sale and retail prices on the Sku."

This reverts commit 04b5c74a60335c4ae8d096be0c0afaee0626ad85.
Revert "Deprecated the implementation of getListPrice() and setListPrice() on SkuImpl. The Sku interface had these marked as @Deprecated already."

This reverts commit bb5f8315a30320ddd6a00f183fcc96740af7ca13.