LMS-1491 screening API: make DTOs serializable

...cisd/openbis/plugin/screening/shared/api/dto/Dataset.java

...penbis/plugin/screening/shared/api/dto/FeatureVector.java

...plugin/screening/shared/api/dto/FeatureVectorDataset.java

...plugin/screening/shared/api/dto/ImageDatasetMetadata.java

...x/cisd/openbis/plugin/screening/shared/api/dto/Plate.java

...bis/plugin/screening/shared/api/dto/PlateSingleImage.java

...lugin/screening/shared/api/dto/WellFeaturesReference.java

...openbis/plugin/screening/shared/api/dto/WellPosition.java