Validate that users request more than 0 resources.

[joaander]

Description

Ensure that users request more than 0 resources.

Motivation and context

Row passes values that the user provides directly through to the scheduler. For example, when a user requests gpus_per_processes = 0, row will dutifully place #SBATCH --gpus-per-task=0 in the submission script. At the same time, row interprets gpus_per_process => Some(_) as a request for GPUs.

This change validates that the user workflow must request at least 1 process, GPU, and/or thread. It informs the user to omit the request to request no resources.

Resolves #86

How has this been tested?

Unit tests verify all new errors.

Checklist:

• I have reviewed the Contributor Guidelines.
• I agree with the terms of the Row Contributor Agreement.
• My name is on the list of contributors (doc/src/contributors.md) in the pull request source branch.
• I have added a change log entry to doc/src/release-notes.md.