[Suggestion] Automatic grouping

[slambo311]

• Description: When a model with multiple meshes is imported or generated, make it so the model's groups and meshes are put into one "master group".
• Why I think this should be implemented It would make it much easier to use more than one model at a time.

If this is already implemented in the downloadable version of blockbench by default, I just use the web version (I mainly use blockbench for school and my school Chromebook has restrictions. Plus, I got crap memory and forget how easy it is to use, so I don't use it on my home laptop either), so it would be nice to have it there too.