Surface: new SVG icon for the workbench, rename others

Replace the hard-coded XPM icon in `InitGui.py` for the workbench
with an SVG file, which at this time is identical to the `Surface` icon.
Change `CMakeLists.txt` to properly install this new icon.

Rename all icons, so that all have the `Surface_` prefix.

Use the new icon names in the viewproviders and task panels.

src/Mod/Surface/Gui/TaskSections.cpp

@@ -100,7 +100,7 @@ void ViewProviderSections::unsetEdit(int ModNum)
 
 QIcon ViewProviderSections::getIcon(void) const
 {
-    return Gui::BitmapFactory().pixmap("BSplineSurf");
+    return Gui::BitmapFactory().pixmap("Surface_Sections");
 }
 
 void ViewProviderSections::highlightReferences(ShapeType type, const References& refs, bool on)