misc: Add multiple machine example

[ruben-arts]

This is a more exotic example of multi env usage

[pavelzw]

Maybe also add import mlx on --mlx and assert torch.cuda.is_available() on --cuda (if this is the correct command) in the train and test scripts?

[ruben-arts]

Maybe also add import mlx on --mlx and assert torch.cuda.is_available() on --cuda (if this is the correct command) in the train and test scripts?

Good idea, I found some other issues, so will continue testing with this.