Recent Projects snapshot images have poor quality

Snapshot images used for Recent Projects view are not good quality.
See the screenshot.

In the capturenodeinstance the size is hardcoded with 150px.

QSize previewImageSize = rootNodeInstance.boundingRect().size().toSize();
if (previewImageSize.isEmpty())
previewImageSize = {150, 150};



if (previewImageSize.width() > 150 || previewImageSize.height() > 150)
previewImageSize.scale({150, 150}, Qt::KeepAspectRatio);

QImage previewImage = rootNodeInstance.renderPreviewImage(previewImageSize);

return previewImage;

This function should use

m_previewSize and "previewSize@Internal" as the states previews.

The plumbing should already be in place since Qt5CaptureImageNodeInstanceServer : public Qt5PreviewNodeInstanceServer.

We should keep the 150px default to avoid breaking UI and use "previewSize@Internal" for the previews to increase the thumbnail size.