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

src/node_dialog_open.cpp

@@ -81,7 +81,7 @@ void NodeDialogOpen::init_controls()
         node->on_selected = [&](NodeDialogOpenItem* target) {
             if (target == current)
                 return;
-            ui::Image thumb = ui::Canvas::I->thumbnail_read(target->m_path);
+            Image thumb = Canvas::I->thumbnail_read(target->m_path);
             auto image_tex = find<NodeImageTexture>("thumb-tex");
             image_tex->tex.destroy();
             image_tex->tex.create(thumb);