Proof of concept: Implement `CoordsIter` based on `geo-traits` traits

[frewsxcv]

• [ ] I agree to follow the project's code of conduct.
• [ ] I added an entry to CHANGES.md if knowledge of this change could be valuable to users.

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Not ready for review. This would be the first incorporation of geo-traits in geo, which could warrant a discussion. Implementing CoordsIter would unlock the first set of algorithms available to be executed directly on non-geo-types types.

[frewsxcv]

cc @kylebarron Maybe relevant to your interests