Consider renaming `type` to `instance_type` (`thing_type`)

[displague]

Other providers use instance_type. Having distinct thing_type configs for each thing adds clarification to the config documentation, I think.

The btobloski repo used size, so there is no established config name in this project.

[displague]

The official recommendation I received was to match the API spec naming as closely as possible. Other providers reuse common names like type, label, and name - so really there is no conflict and, in fact, it makes naming more predictable.

We're not going to rename things to this longer format.