Feature/night sky items (#2613)

* added night sky items and camera event
---------

Co-authored-by: Alexander Bock <alexander.bock@liu.se>

include/openspace/navigation/orbitalnavigator.h

@@ -98,6 +98,8 @@ public:
     void tickIdleBehaviorTimer(double deltaTime);
     void triggerIdleBehavior(std::string_view choice = "");
 
+    void tickMovementTimer(float deltaTime);
+
     Camera* camera() const;
     void setCamera(Camera* camera);
     void clearPreviousState();
@@ -253,6 +255,8 @@ private:
     IdleBehavior _idleBehavior;
     float _idleBehaviorTriggerTimer = 0.f;
 
+    float _movementTimer = 0.f;
+
     /**
      * Decomposes the camera's rotation in to a global and a local rotation defined by
      * CameraRotationDecomposition. The global rotation defines the rotation so that the