remove ParticleDistribution and related classes from GUI

GUI/coregui/Models/DomainObjectBuilder.cpp

GUI/coregui/Models/GUIDomainSampleVisitor.cpp

GUI/coregui/Models/GUIExamplesFactory.cpp

GUI/coregui/Models/ItemCatalog.cpp

GUI/coregui/Models/ParticleDistributionItem.cpp

GUI/coregui/Models/ParticleDistributionItem.h

GUI/coregui/Models/SampleValidator.cpp

GUI/coregui/Models/SampleValidator.h

GUI/coregui/Models/SessionItemUtils.cpp

GUI/coregui/Models/TransformFromDomain.cpp

GUI/coregui/Models/TransformFromDomain.h

GUI/coregui/Models/TransformToDomain.cpp

GUI/coregui/Models/TransformToDomain.h

GUI/coregui/Views/MaterialEditor/MaterialItemUtils.cpp

GUI/coregui/Views/RealSpaceWidgets/RealSpaceBuilder.cpp

GUI/coregui/Views/RealSpaceWidgets/RealSpaceBuilderUtils.cpp

...egui/Views/RealSpaceWidgets/RealSpaceMesoCrystalUtils.cpp

GUI/coregui/Views/SampleDesigner/DesignerHelper.cpp

...coregui/Views/SampleDesigner/ParticleDistributionView.cpp

GUI/coregui/Views/SampleDesigner/ParticleDistributionView.h