Make device spinner config composeable

It would be nice to be able to make configs composeable, where a device, or many devices might be defined elsewhere at a separate filepath or URL.

To accomplish this, we'd need some higher level settings and schema logic to read the yaml and then resolve it into a final flattened config. We would likely also want a way to save the resolved config to a file if requested.

Additionally, it would be nice to support overriding some fields from these configs specified elsewhere, such that the resolved result has specific fields altered.

The overall win is readability where complicated "sub"-devices can be reused with minor override adjustments.