HCoS: Anchor point redundancy of pseudowire subscriber logical interfaces

Full hierarchical CoS is provided for stateful anchor point redundancy of pseudowire subscriber logical interfaces. Both transport and services logical interfaces created for the pseudowire subscriber logical interface are stacked on the underlying redundant logical tunnel control logical interface. This logical interface stacking model is used for both redundant and non-redundant pseudowire subscriber logical interfaces. Hierarchical CoS is supported and configured the same on both redundant and non-redundant pseudowire subscriber logical interfaces.