Support SLURM array jobs in babs-submit (#188)

* Initial changes to implement array submission

Not all babs arguments are modified yet, such as babs-submit --job

* fix generate_job_submit_template so that test_job_template does not include max_array

* Additional fix for babs-check-setup and run black on babs/babs.py

* change test_babs_init to use slurm instead of sge

* update test_babs_check_setup to use slurm instead of sge

Author: tien-tong