Report EoL/EoS data on physical entities

As noted here and here, End of Support dates are currently not able to be reported correctly for modules, line cards, and switch stacks since only one EoS date can be entered per NCM entity.  EoS data needs to be based on the physical inventory of an entity such as a 3750 stack where stack members may have different EoS dates, and 6509 Catalyst chassis or 7206vxr routers, where specific line cards or port adapters may go EoS at a different date than the chassis.