Use an enum for errors instead of an NonZeroI32

[ultimaweapon]

Discussed in https://github.com/obhq/obliteration/discussions/769

^{Originally posted by SuchAFuriousDeath March 27, 2024} I think this could make some functions better optimized.

[SuchAFuriousDeath]

How should the enum be named? PS4Error? PS4Errno?

[ultimaweapon]

I totally forget we already used Errno name. No idea about the name yet but we should find a better name than PS4Error and PS4Errno.

[ultimaweapon]

We should use Errno and rename the current Errno trait to something else.

[ultimaweapon]

My idea is AsErrno so it is matched with std.