qfds.sh: Add option to use all available cores

[mcgratta]

No description provided.

[mcgratta]

This PR adds a flag to qfds.sh called -c that removes the node limit for a job. That is, if you do this

qfds.sh -p 800 -c -q all my_job.fds

then the job will run over the entire cluster looking for any available core. All that the -c does is remove

#SBATCH --nodes=...

allowing Slurm to use any core within the given queue.

BTW, c stands for cram, as in cram the job onto the cluster.