LMS-2081 minor: simplify API interface for analysis registration

.../cisd/openbis/dss/etl/dto/api/impl/FeatureDefinition.java

...dss/etl/dto/api/impl/FeatureVectorDataSetInformation.java

...sx/cisd/openbis/dss/etl/dto/api/impl/FeaturesBuilder.java

...sx/cisd/openbis/dss/etl/dto/api/v1/FeatureDefinition.java

...x/cisd/openbis/dss/etl/dto/api/v1/IFeatureDefinition.java

...isd/openbis/dss/etl/dto/api/v1/IFeatureVectorDataSet.java

...msx/cisd/openbis/dss/etl/dto/api/v1/IFeaturesBuilder.java

...is/dss/etl/featurevector/CsvToCanonicalFeatureVector.java

.../dss/etl/featurevector/FeatureVectorStorageProcessor.java

...bis/dss/etl/dto/api/impl/FeatureDefinitionValuesTest.java