move IndicesService & IMappingService interface back to Indexer service
Related os-core-common MR: 136
Move IndicesService & IMappingService interface back to Indexer core module. These are only two interfaces that were in os-core-common lib, all other Indexer interfaces are present in Indexer core module.
This change-set makes Indexer interfaces consistent and also remove Elastic dependencies from os-core-common. Elasticsearch is only used by Search and Indexer service but all os-core-common consumer services were inheriting Elasticsearch dependencies.