Split out Vendor code into a separate module.

[ndouglas]

Story

There's Vendor-related code in the GUI, in the runstate, as a mode of a specific runstate value, etc. It's not a terribly large or complicated system, but it's pretty spaghetti.

Ideally, it would all exist in a single module. I don't really know how to break it out cleanly, but maybe I'll figure it out.

I'll timebox this at two hours. Hopefully it'll take a lot less time than that.

Acceptance Criteria

• [x] Vendor code exists in a vendor module.

Implementation Notes

[ndouglas]

Actual time ~40 minutes.