MaterialEditor: add the export materials feature
Feature will be relevant when !4939 (merged) will be merged
When the feature will be available in VTK, add some code and UI into the pqMaterialEditor to handle exporting a material into Json :
/ .h
SLOT:
void exportMaterials();
// .cxx
QObject::connect(this->Internals->Ui.ExportMaterials, SIGNAL(clicked()), this, SLOT(exportMaterials()));
// .ui
<item>
<widget class="QToolButton" name="ExportMaterials">
<property name="toolTip">
<string>Export materials</string>
</property>
<property name="text">
<string/>
</property>
<property name="icon">
<iconset resource="../../../Components/Resources/pqComponents.qrc">
<normaloff>:/pqWidgets/Icons/pqSave.svg</normaloff>:/pqWidgets/Icons/pqSave.svg</iconset>
</property>
</widget>
</item>