remove ui namespace which is not really used, move CameraData in camera_modes.h to avoid the inclusion of canva.h

src/node_viewport.h

@@ -7,7 +7,7 @@
 class NodeViewport : public Node
 {
 public:
-    std::unique_ptr<ui::Plane> m_faces;
+    std::unique_ptr<Plane> m_faces;
     std::unique_ptr<Sampler> m_sampler;
     uint16_t m_tex_id;
     glm::vec2 drag_start;