Setup automated tests in an ephemeral slurm cluster

[abhidg]

https://github.com/giovtorres/slurm-docker-cluster sets up a Slurm cluster with two nodes on a local machine using Docker. Implement a shell script to run cats within a Slurm cluster and check:

(i) job is in queue
(ii) job start time is expected start time printed out by CATS.

This will be potentially useful for #72

• Run docker compose setup locally
• Modify Dockerfile from slurm-docker-cluster to install cats
• Write shell script to test scontrol output
• Setup GitHub CI