[Indexer] Support for indexing documents with nested arrays of objects

JSON documents with nested arrays of objects are not currently indexed by the Indexer. The capability needs to be added so that search queries on such documents can be executed. Understanding that there are performance issues with allowing too many levels of nested arrays to be search, it is proposed that limitations be put on the number of levels allowed for nested indexing. Additionally, in cases where an abstract base schema is defined for the attribute type (example: AbstractFacilityEvent in AbstractFacility.json), the indexer should only support indexing the abstract base schema entities and not extensions added to the concrete definition.