Add better view for AssetLibrary

I think we should set better asset thumbnails for world environmental assets.

For example, a mirror ball for the world environment, or a camera display pointing to the y-axis at the origin (for EEVEE, because panoramic cameras are not supported)

Yes, I would like to have a button to set the view content as an asset thumbnail with one click(This would be very useful, for everyone!) ）

The default thumbnail serves no purpose, and the user simply can't understand what it is: