CLI script not accounting for user's environment specific slurm args requirements

[ManavalanG]

A reviewer ran into error due to slurm related issues when slurmpy attempts to submit the parent quac job to slurm.

We believe we fixed a variation of this issue in #73 where snakemake would be submitting jobs to slurm. Ideally we should have fixed above issues as part of that PR, but we didn't catch it back then.

Planned solution:

• When CLI script gathers slurm args to use with parent quac job submission to slurm:

    slurm_resources = {
        "partition": args.slurm_partition,
        "ntasks": "1",
        "time": slurm_partition_times[args.slurm_partition],
        "cpus-per-task": "1" if args.subtasks_slurm else "4",
        "mem-per-cpu": "8G",
    }

add a step to read cluster config file and include any args that are not already in slurm_resources

• Remove default for --cluster_config and force user to provide it manually. Its help message will instruct the user to use configs/cluster_config.json as template and edit to match their slurm environment. We think this will let user take a second and set up the configs as needed.
• Update docs to include example on how to edit cluster config to match user's slurm env.

[ManavalanG]

Quick note - solution we ended up using was to provide slurm info as a input config file.