refactor: don't use constant when meaning can be derived from value itself

...ge/solidify/service/CompositionResourceClientService.java

...java/ch/unige/solidify/service/ResourceClientService.java

...a/ch/unige/solidify/controller/ApplicationController.java

...in/java/ch/unige/solidify/controller/OrcidController.java

...unige/solidify/controller/ResourceReadOnlyController.java

.../unige/solidify/controller/SolidifySitemapController.java

...ava/ch/unige/solidify/test/doc/RestDocsDocumentation.java

...unige/solidify/test/executor/SolidifyExecutorTestDoc.java

...rc/main/java/ch/unige/solidify/test/helper/FileUtils.java

...java/ch/unige/solidify/test/helper/RestDocsTemplates.java

.../abstractservice/IndexFielAliasRemoteResourceService.java

...t/abstractservice/IndexMetadataRemoteResourceService.java

...x-model/src/main/java/ch/unige/solidify/IndexUrlPath.java

...ge/solidify/controller/index/IndexSettingsController.java

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

.../settings/elasticsearch/ElasticsearchSettingsService.java

...oai-model/src/main/java/ch/unige/solidify/OAIUrlPath.java

.../ch/unige/solidify/business/OAIMetadataPrefixService.java

.../unige/solidify/controller/oai/OAIProviderController.java

...h/src/main/java/ch/unige/solidify/service/OAIService.java