Isolate irrlicht references and use a singleton (#6041)

* Add Device3D class which will contain IrrlichtDevice interface

move getSupportedVideoDrivers to Device3D

Add Device3D singleton & use it in various places

Rename Device3D to Rendering engine & add helper functions to various device pointers

More singleton work

RenderingEngine owns draw_load_screen

move draw functions to RenderingEngine

Reduce IrrlichtDevice exposure and guienvironment

RenderingEngine: Expose get_timer_time() to remove device from guiEngine

Make irrlichtdevice & scene manager less exposed

* Code style fixes

* Move porting::getVideoDriverName, getVideoDriverFriendlyName, getDisplayDensity, getDisplaySize to RenderingEngine

Fix XORG_USED macro -> RenderingEngine + create_engine_device from RenderingEngine constructor directly

* enum paralax => enum parallax

src/guiEngine.h

@@ -150,11 +150,9 @@ public:
 	 * @param smgr scene manager to add scene elements to
 	 * @param data struct to transfer data to main game handling
 	 */
-	GUIEngine(irr::IrrlichtDevice *dev,
-			JoystickController *joystick,
+	GUIEngine(JoystickController *joystick,
 			gui::IGUIElement *parent,
 			IMenuManager *menumgr,
-			scene::ISceneManager *smgr,
 			MainMenuData *data,
 			bool &kill);
 
@@ -192,8 +190,6 @@ private:
 	/** update size of topleftext element */
 	void updateTopLeftTextSize();
 
-	/** device to draw at */
-	irr::IrrlichtDevice     *m_device = nullptr;
 	/** parent gui element */
 	gui::IGUIElement        *m_parent = nullptr;
 	/** manager to add menus to */