Actually check boolean env vars

[Jeidnx]

Check if boolean env vars are either true or 1 instead of just checking if the env var exists.
I also ran cargo fmt so the code adheres to the rust standard

[Bnyro]

I'd prefer having a

fn check_env_bool(&str) -> bool {}

to use for uds and ipv4 instead of repeating the code.
And the formatting changes should probably be done in a different PR :)

[Bnyro]

Thank you! :P