Fix the versioning on multi-node training.
> 
> 
> Please update the docstring of exp_manger so that it matches the new behaviour.
> Please add a note that the behaviour of this argument changed as of version 1.0.0.

Added to the docstring.
Used resume_if_exists instead of checking the Slurm to void creating the version folders. So whenever resume_if_exists  is enabled, we should skip creating the versions otherwise training can not continue.