private boolean isFileReferenceInUse(FileReference fileReference) {
        return getFileReferencesInUse().contains(fileReference.value());
    }
Deletes an application and associated resources

@return true if the application was found and deleted, false if it was not present
@throws RuntimeException if deleting the application fails. This method is exception safe.
configserver/src/main/java/com/yahoo/vespa/config/server/ApplicationRepository.java