AK: Add Eternal<T> and use it in various places.

This is useful for static locals that never need to be destroyed:

Thing& Thing::the()
{
    static Eternal<Thing> the;
    return the;
}

The object will be allocated in data segment memory and will never have
its destructor invoked.

Applications/ProcessManager/MemoryStatsWidget.cpp

@@ -106,5 +106,5 @@ void MemoryStatsWidget::paint_event(GPaintEvent& event)
 {
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
-    StylePainter::the().paint_surface(painter, rect());
+    StylePainter::paint_surface(painter, rect());
 }