Simple tools for RimWorld

Planned features:

• Backup settings and mods. Initial goal.
• GUI? On the fence, here
• MacOS support. Maybe one day. I don't currently have a Mac.
• Linux support.
• Find install location based on Steam library configurations. Registry?
• DRM free version support.
• Workshop mod support for DRM free?
• Modpack system?
• Implement integration and end to end tests. Currently only testing internal semver module.

Notes

• There are no libraries for iterating all steam libraries anywhere, so I'll have to implement one myself. Definitely something to implement after core functionality.
• Currently plenty of #[allow(dead_code)]. Partially to get rid of compiler warnings for what I'm currently working on, and partially because compiling main.rs will trip dead code warnings for unused code that is still exported in lib.rs. Understandable, yet aggravating nonetheless.