SLURM: specifying extra arguments for GPU binding

Nobody has claimed this yet.

Is there a recommended way to specify extra SLURM options for GPU bindings?

I tried using the `args:` batch block key (https://maestrowf.readthedocs.io/en/latest/Maestro/scheduling.html), but the options did not get propagated to the *.sh job script.

Following https://github.com/LLNL/maestrowf/issues/340, the workaround I've used so far is to specify these options as part of the run command so that they get copied into the job script:
```
- name: run-sim
description: Run the simulation.
run:
cmd: |
#SBATCH --mem=0
#SBATCH --constraint="scratch"
#SBATCH --ntasks-per-node=4
#SBATCH --cpus-per-task=16
#SBATCH --gpus-per-task=1
#SBATCH --gpu-bind=none

srun bash -c "
export CUDA_VISIBLE_DEVICES=\$((3-SLURM_LOCALID));
$(BINARY_PATH) -i $(generate-infile.workspace)/params.in" > logfile.txt
depends: [generate-infile]
nodes: 1
exclusive: True
walltime: "00:10:00"
```

Start by tracing how the `args:` batch block key is handled when the generated `*.sh` job script is built. Compare it with the documented run-command workaround and verify that extra SLURM options, including GPU-binding options, are propagated into the script.

Written by the indexing model from the issue text.