Back up the design library and configuration when loading them

**What do you want to see?**
When loading the design library or the configuration, copy the file to a backup in case it gets corrupted.

**How would it help players?**
If for whatever reason there's an problem loading the file, there will be a backup of it so that when it's saved again, the file can be restored from its corrupted state.

**Alternatives**
We could keep a single backup or a certain number of backups or backups going back a certain amount of time. Maybe this could be configurable? Or maybe that would be too much?

**Screenshots and mockups**
N/A

**Things to consider**
???