Replace more self-made icons with "Material Design" family

...regui/Views/ImportDataWidgets/RealDataSelectorToolBar.cpp

...coregui/Views/InstrumentWidgets/InstrumentViewToolBar.cpp

GUI/coregui/Views/SampleDesigner/SampleDesigner.qrc

GUI/coregui/Views/SampleDesigner/SampleToolBar.cpp

GUI/coregui/Views/SampleDesigner/images/alpha-m-box.svg

GUI/coregui/Views/SampleDesigner/images/arrow-top-left.svg

...ui/Views/SampleDesigner/images/camera-metering-center.svg

GUI/coregui/Views/SampleDesigner/images/delete.svg

GUI/coregui/Views/SampleDesigner/images/hand-right.svg

GUI/coregui/Views/SampleDesigner/images/rotate-3d.svg

GUI/coregui/Views/SampleDesigner/images/toolbar_center.png

GUI/coregui/Views/SampleDesigner/images/toolbar_hand.png

...ui/Views/SampleDesigner/images/toolbar_materialeditor.png

GUI/coregui/Views/SampleDesigner/images/toolbar_pointer.png

GUI/coregui/Views/SampleDesigner/images/toolbar_recycle.png

GUI/coregui/coregui.qrc

GUI/coregui/images/content-copy.svg

GUI/coregui/images/delete.svg

GUI/coregui/images/import.svg

GUI/coregui/images/shape-square-plus.svg