MESH-CLASS default parameters

[kasra-keshavarz]

I noticed that ECCC/NHS-NAS team has access to a default parameter set for CLASS components. This needs to be implemented within MESHFlow instead of those "filler" values that are currently included in the default configurations.

Current default "filler" parameters are listed here: https://github.com/CH-Earth/meshflow/blob/main/src/meshflow/templates/default_CLASS_parameters.json.

I include Zelalem and Sujata later on this issue.