Inspector: Show remote object properties in a table view

This patch expands the object model of this program quite a bit.
We now have a RemoteProcess object that contains a list of remote root
RemoteObject objects.

The RemoteProcess vends a RemoteObjectGraphModel&, and indices in that
model have internal_data() pointing to a corresponding RemoteObject.
RemoteObjects in turn vend a RemoteObjectPropertyModel&, which is what
we use to show the object properties.

This is pretty cool :^)

DevTools/Inspector/RemoteObject.cpp

@@ -0,0 +1,13 @@
+#include "RemoteObject.h"
+#include "RemoteObjectPropertyModel.h"
+
+RemoteObject::RemoteObject()
+    : m_property_model(RemoteObjectPropertyModel::create(*this))
+{
+}
+
+RemoteObjectPropertyModel& RemoteObject::property_model()
+{
+    m_property_model->update();
+    return *m_property_model;
+}