[#42][Fix] remove setting the active camera automatically when adding a new camera

Per default: index = 0 is the active camera. The user should determine himself via setActiveCamera which camera should be active

modules/camera/src/vkcv/camera/CameraManager.cpp

@@ -81,7 +81,6 @@ namespace vkcv{
         m_cameras.push_back(camera);  // TODO: is there another way we can do this?
         m_cameras.back().setPerspective(glm::radians(60.0f), m_window.getWidth() / m_window.getHeight(), 0.1f, 10.0f);
         m_cameraControllerTypes.push_back(ControllerType::NONE);
-        setActiveCamera(m_cameras.size() - 1);
         return m_cameras.size() - 1;
     }