Preconfigured union for a "plain" python data structures

Review the existing preconfigured converters and PythonConverter configuration to identify the entry point for adding another preset. Use the proposed plain Python passthrough types and collection overrides as the acceptance criteria, then verify that the new converter preserves those values and collections during conversion.

There are preconfigured converters for the various serialization formats, but I have found need for a converter specific to what I will call "plain" Python.

Basically:

PassThroughTypes: TypeAlias = str | bool | int | float | bytes | None

def python_make_converter(
    *args: Any,
    **kwargs: Any,
) -> PythonConverter:

    # configure specific overrides for this converter
    kwargs["unstruct_collection_overrides"] = {
        # rich built-in types are maintained, rather than all dumped
        # into lists
        Sequence: tuple,
        MutableSequence: list,
        Set: frozenset,
        MutableSet: set,
        Counter: lambda c: Counter(**{k: v for k, v in c}),
    }

    converter = PythonConverter(*args, **kwargs)

    # passthrough union types
    configure_union_passthrough(PassThroughTypes, converter)

    return converter

Just some context for what I am doing that warranted making this concrete versus the more plain cattrs.global_converter. I am using the converter to generate "patches" that all happens within Python and the above to be very useful.

I would propose that a new preconfigured converter be made similar to the others. But I can understand it not being high priority, in which case this issue may help someone else :)