Allow seeds to be set for individual batches

[orionarcher]

Currently, the same seed on systems with different batch sizes will yield different random numbers. This should be modified so it's possible to get different batch sizes with the same seed.

[sacredvoid]

Was trying to contribute to TorchSim, trying to find a good issue to start with, this one seems like it's been fixed. Can someone on the team confirm?

[thomasloux]

@sacredvoid you should have a look on #286