Auto-parsing of Python schemas to extrude StructTypes representations in Julia

**Describe the feature you'd like**
It should be possible to use the Smithy representation of the [Amazon Braket Schemas](https://github.com/amazon-braket/amazon-braket-schemas-python) to automatically generate JSON versions of all the Braket Schemas, which `JSON3.jl` and `StructTypes.jl` can then digest to generate the corresponding Julia types.

**Is this feature already present in the Python SDK?**
N/A

**How would this feature be used? Please describe.**
This would make it possible to keep the `Braket.jl` versions of the schemas up to date automatically.

**Describe alternatives you've considered**
Currently this must be done by hand.

**Additional context**
It's necessary to replicate some of the implicit information encoded by the type hierarchy in Python that is currently represented with traits in Julia, e.g. target count. Also, support for the Pydantic restrictions on fields would be helpful.