Avoids:
```
warning: the following packages contain code that will be rejected by a future version of Rust: ntapi v0.3.7
note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 36`
```
Avoid using serde for mapping between Lua and Rust for the `Config`
struct.
This improves the build speed of the config crate by 2x; it goes down
from 30 seconds to 9 seconds on my 5950x.
