[FEATURE/BUGFIX] Replaces steel wires with copper wires

[Noah Buttes]

This patch aims to address the issue presented in this bug report. It does so by creating a terrestrial analogue of pharosium in the form of copper. It then applies this material to all forms of power cables in place of steel.

Patch:
https://github.com/goonstation/goonstati...s?expand=1

Note: I'm aware that copper is actually a really great conductor in reality, but let's just pretend this copper is really impure due to Nanotrasen's cost-cutting policies.