clean up abandoned shopping carts and their cart quantity items so carts can be reused later

[cbmarcum]

In many cases this is being caused by client pages (usually in layouts) using the ShoppingCartService to get an item count usually for display in the menubar.
ex.
a call to shoppingCartService.getItems()?.size()
getItems calls getShoppingCart() which in turn calls createShoppingCart() if a current cart is not found which creates the mystery carts.

add a scheduled task to reset the session id to a fake value and try to use these first before creating new carts.

[cbmarcum]

Refs #65.