Update CAN docs

Needs some additional information, i.e. what the CAN Bus is, how it relates to configuring devices with ports, and what optimizing usage does

No file, wiki page, or entry point is named. First locate the existing CAN documentation and review how device ports and usage optimization are currently described; done means the page explains what CAN Bus is, how it relates to configuring devices with ports, and what optimizing usage means.

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