Add ghost component (#1409)

will be used to migrate other Player functionality in a future PR.

Tested that I can login still.

dGame/dComponents/GhostComponent.cpp

@@ -0,0 +1,4 @@
+#include "GhostComponent.h"
+
+// TODO Move ghosting related code from Player to here
+GhostComponent::GhostComponent(Entity* parent) : Component(parent) {}