WIP: Feature/#415 use resource pointer directly as component

We use ResourcePointers directly instead of through HandleComponents which only wrap the resource pointer.

Please take a close look. I needed to declare the copy constructor and operator of Component from delete to default. That should in general be no problem, since we store the components within the entities in unique_ptr what makes them non-copyable.

demos/viewer/src/viewer.cpp

@@ -23,8 +23,6 @@
 #include <chrono>
 #include <iostream>
 #include <memory>
-#include <string>
-#include <utility>
 #include <vector>
 
 #include "phx/core/engine.hpp"
@@ -38,22 +36,14 @@
 #include "phx/input/input_system.hpp"
 #include "phx/rendering/auxiliary/splash_screen.hpp"
 #include "phx/rendering/components/light.hpp"
-#include "phx/rendering/components/material_handle.hpp"
-#include "phx/rendering/components/mesh_handle.hpp"
 #include "phx/rendering/components/transform.hpp"
-#include "phx/rendering/rendering_system.hpp"
 #include "phx/resources/loaders/assimp_model_loader.hpp"
 #include "phx/resources/loaders/openvr_resource_loader.hpp"
 #include "phx/resources/loaders/scene_loader.hpp"
-#include "phx/resources/types/mesh.hpp"
-#include "phx/resources/resource_declaration.hpp"
 #include "phx/resources/resource_manager.hpp"
-#include "phx/resources/resource_pointer.hpp"
-#include "phx/phoenix.hpp"
 #include "phx/setup.hpp"
 
 #include "navigation_behavior.hpp"
-#include "rotation_behavior.hpp"
 #include "viewer_system.hpp"
 
 #if defined __clang__