[i88] GUI refactoring: remove mappers from JobItem ()

GUI/Model/Data/DataItem.cpp

GUI/Model/Data/DataItem.h

GUI/Model/Job/JobItem.cpp

GUI/View/Common/ItemComboWidget.cpp

GUI/View/Loaders/QREDataLoader.cpp

GUI/View/Plot2D/IntensityDataWidget.cpp

GUI/View/PlotComparison/FitComparisonWidget.cpp

GUI/View/PlotComparison/FitComparisonWidget1D.cpp

GUI/View/PlotSpecular/SpecularDataWidget.cpp

GUI/View/PlotUtil/IntensityDataPropertyWidget.cpp

GUI/View/PlotUtil/IntensityDataPropertyWidget.h

GUI/View/Projection/IntensityDataProjectionsWidget.cpp

GUI/View/Projection/ProjectionsEditor.cpp

GUI/View/Projection/ProjectionsEditor.h

GUI/View/PropertyEditor/SpecularDataPropertyWidget.cpp

GUI/View/PropertyEditor/SpecularDataPropertyWidget.h