SendCutSend instructions for getting metal mount created

Since I've never used SendCutSend before, it'd be nice to have a step-by-step set of instructions for ordering the 2U faceplate in metal from them (mostly what options to choose), and notes about potential costs and shipping times.

(There is no rush to do this of course!)

Separately, maybe someone in the community would like to organize a group buy? Logistics mostly kill that sort of thing, but if multiple people in one small region might want metal parts, it would save money to have one person order multiples, then distribute them locally.

And with flat 10" parts, shipping costs aren't that bad.

Start by checking the repository's existing documentation for the 2U faceplate and any current SendCutSend guidance. Document the ordering options, potential costs, shipping times, and any clearly supported group-buy notes; the work is done when a reader can follow the steps to order the metal part.

Written by the indexing model from the issue text.