Add thumbnails for 3d print objects stl, 3mf

[mrspaceman]

Add support for displaying thumbnails for 3d printing formats STL and 3MF.

• https://en.wikipedia.org/wiki/STL_(file_format)
• https://en.wikipedia.org/wiki/3D_Manufacturing_Format#:~:text=3MF%20is%20an%20XML%2Dbased,represented%20in%20the%20STL%20format.
• https://3mf.io/

[HeavenVolkoff]

Hello @mrspaceman, thanks for the suggestion. There is already a discussion for 3D objects thumbnail/preview, so I will close this in favor of the original one #2454