Redundant format field in Model Runtime section

[duckontheweb]

Model Runtime Fields: If type already needs to be set to docker or onnx, why provide a format field with the same values in properties?

Originally raised in #25

[duckontheweb]

Originally, we had talked about supporting a variety of serialization and containerization formats. I originally intended the type field to be something like "containerized" or "serialized" and then the format field would be more specific within that (e.g. "onnx" or "pytorch" for the "serialization" type).

Perhaps we should move back to that structure given that there may be interest in adding new formats in the future (see #26)?