ui: moved subnode layouting from GraphView to GraphController

This change moves nested layouting of the Graph to GraphController. The DummyNodes get the correct size assigned, as
well as a visible flag. Mouse interaction with the Graph is now handled via the GraphController, which makes it
easier to undo them or reuse the changed state after graph updates.

src/lib/component/view/GraphView.cpp

@@ -1,5 +1,14 @@
 #include "component/view/GraphView.h"
 
+GraphView::Metrics::Metrics()
+	: width(0)
+	, height(0)
+	, typeNameCharWidth(0.0f)
+	, variableNameCharWidth(0.0f)
+	, functionNameCharWidth(0.0f)
+{
+}
+
 GraphView::GraphView(ViewLayout* viewLayout)
 	: View(viewLayout, Vec2i(100, 100))
 {