Add EntitySet to the list of possible target for terms ApplySupported, CustomAggregate

1. Replace EntityType with EntitySet to the list of model elements applicable for these two terms. Remove EntityType from related terms CustomAggregate, ApplySupported, Aggregatable, Groupable. 2. Extend complex type NavigationPropertyRestriction in the Capabilities vocabulary to describe the different aggregation support and restrictions between different navigation path, including collections that can only be reached from containment navigation properties. Add this type definition to the Aggregation vocabulary.