Add Carbon Mod to Rust

[eumario]

This PR follows the same methodology for installing Oxide, for the Carbon modding system for Rust. Same options are implemented for Carbon, as well as safety checks to ensure that one or the other mod systems are enabled, not both at the same time.

[ervins0x]

When this is planned to get merged?

[eberdt]

@Dids @eumario Is there a chance to merge this request? I think the feature would be a super plus and lgtm