SP-302 / BIS-214 : Improvements to PathInfoDb

...penbis/dss/generic/server/EncapsulatedOpenBISService.java

...enbis/dss/generic/shared/HierarchicalContentProvider.java

...enbis/dss/generic/shared/IEncapsulatedOpenBISService.java

...penbis/dss/generic/server/DatasetDownloadServletTest.java

.../cisd/openbis/dss/generic/server/DssServiceRpcV1Test.java

...s/dss/generic/shared/HierarchicalContentProviderTest.java

...a/ch/systemsx/cisd/openbis/generic/server/ETLService.java

...ystemsx/cisd/openbis/generic/server/ETLServiceLogger.java

...neric/server/business/bo/datasetlister/DatasetLister.java

.../business/bo/datasetlister/DatasetLocationNodeRecord.java

...eric/server/business/bo/datasetlister/IDatasetLister.java

...erver/business/bo/datasetlister/IDatasetListingQuery.java

...systemsx/cisd/openbis/generic/shared/IETLLIMSService.java

...isd/openbis/generic/shared/basic/dto/DatasetLocation.java

...openbis/generic/shared/basic/dto/DatasetLocationNode.java

...is/generic/shared/basic/dto/ExternalDataLocationNode.java

...penbis/generic/shared/basic/dto/IDatasetLocationNode.java