[LMS-1907] introduced UnicodeUtils and used it e.g. in all loaders

...ce/java/ch/systemsx/cisd/common/parser/TabFileLoader.java

.../java/ch/systemsx/cisd/common/utilities/UnicodeUtils.java

...penbis/generic/client/web/server/CommonClientService.java

...s/generic/client/web/server/FileExportServiceServlet.java

...emsx/cisd/openbis/generic/shared/basic/BasicConstant.java

.../cisd/openbis/generic/shared/parser/BisTabFileLoader.java

...bis/generic/shared/parser/SampleUploadSectionsParser.java

...enbis/plugin/generic/client/web/server/DataSetLoader.java

...is/plugin/generic/client/web/server/ExperimentLoader.java

...nbis/plugin/generic/client/web/server/MaterialLoader.java

...in/generic/client/web/server/UpdatedExperimentLoader.java