Use OsString for System

[CryZe]

This uses OsString for the methods on System.

[CryZe]

This is where maybe some of these start to not necessarily make sense. It's just one of N branches I created back then after switching everything.

[GuillaumeGomez]

Indeed. What's your logic backing this change? I don't expect any of these cases to ever handle non-utf8 strings.

[CryZe]

There's no logic, I just did a full conversion of the entire crate (for fun? no idea, don't remember). We can close this and instead discuss which APIs would benefit from it, so I can open those PRs (or none at all). Alternatively maybe it can be similar to std::env::args / std::env::args_os. Where internally it's all managed as OsString, but there's generally convenience methods for when you really expect UTF-8 strings.

[GuillaumeGomez]

At least in this case, the strings are not meant to be reused in sysinfo API, so that seems more complex than necessary as we tend to use String and not OsString in general.

I think "if it's used in sysinfo API" is a good metric to talk whether or not an API should use OsString or not. What do you think?