Model config as first class citizen as a param

[sroussey]

Right now, the schemas say the models params can be a named one to lookup, or a config, but the reality is that it is not implemented.

So, need to see if value is a name, and then do a lookup via model registry as we do now, or if config then use directly. Will likely need to rejig types a little since a model config is a model record without an id field.

Later a model record could include model internals, etc that we get from the config.json files (a little of which we display in the model library at workglow.dev).

Related: model config schemas are big and ugly, and might get be to finally use $ref.