Spin-off from discussion in #1288 around menus and menu items: the proposed menuAddOn piece of that design needs further discussion.

http://webschemas.org/menuAddOn

"Additional menu item(s) such as a side dish of salad or side order of fries that can be added to this menu item. Additionally it can be a menu section containing allowed add-on menu items for this menu item."

Per #1288, decision is to move that property into Pending, the rest has rough consensus and is going directly into Core.

/cc @gmackenz