Convert parm/configs from @TEMPLATE@ to Jinja {{ TEMPLATE }}

[aerorahul]

What new functionality do you need?

The experiment config files under parm/config/<system>/config.* are templated in the format @TEMPLATE@.
setup_expt.py as a result has to do extra work mapping the keys from the yaml's providing the defaults to match these keys. This adds unnecessary complexity and custom code that can be easily replaced by using standard Jinja templating. This effort translates to users unfamiliar with the inner workings of the global-workflow.

What are the requirements for the new functionality?

• Use standard templating practices e.g. jinja instead of ad hock methods while maintaining existing functionality.

Acceptance Criteria

• All @TEMPLATE@ type appearances from config.* are replaced w/ {{ TEMPLATE }}
• Experiment directories generated before and after this change are identical for all the test cases
• XML's generated before and after this change are identical for all test cases

Suggest a solution (optional)

No response