refactor(index): simplify hierarchy of controllers used for index metadata CRUD

.../java/ch/unige/solidify/service/NoSqlResourceService.java

...nige/solidify/controller/IndexDataReadOnlyController.java

...controller/IndexResourceReadOnlyWithSearchController.java

.../java/ch/unige/solidify/service/IndexResourceService.java

...in/java/ch/unige/solidify/service/IndexSearchService.java

.../solidify/controller/index/IndexDataSearchController.java

...e/solidify/controller/index/IndexDataWriteController.java

...h/unige/solidify/controller/index/IndexingController.java

...fy/index/indexing/elasticsearch/ElasticsearchService.java

...index/indexing/inmemory/InMemoryIndexMetadataService.java

...ige/solidify/index/indexing/inmemory/InMemoryService.java

...ge/solidify/service/IndexSettingIndexMetadataService.java