Added UID as a slurm cluster submit option

[maerteijn]

According to https://slurm.schedmd.com/sbatch.html:

--uid=

Attempt to submit and/or run a job as user instead of the invoking user id.
The invoking user's credentials will be used to check access permissions for the target partition. User root may use this option to run jobs as a normal user in a RootOnly partition for example. If run as root, sbatch will drop its permissions to the uid specified after node allocation is successful. user may be the user name or numerical user ID.

Would be nice to have this feature (and a pypi release), thanks in advance for reviewing