Introduce schema for Quantum Volume jobs

[cosenal]

Description

A schema for defining the parameters of a Quantum Volume job is introduced here, along with tooling for loading and validating job input files that instantiate said schema.

I tried to keep this PR the less distruptive as possible, but there are other changes that are due in follow-up PRs:

1. create dataclasses for collecting specific benchmark parameters
2. decoupling dispatching from qv Generalize dispatch_bench_job function #65

Issue ticket number and link

Fixes #61

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Unit tests have been added for the schema validator utilities.
It was also smoke tested with the following command:

python metriq_gym/dispatch_qv.py job.json --backend qasm_simulator --provider ibmq

with job.json being a file created by the user.

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules (or not applicable)

[cosenal]

Don't mind me sorting the dependencies alphabetically here.
The only addition is jsonschema

[cosenal]

@vprusso comments addressed. PTAL

[vprusso]

Nice, LGTM!