Implement a better file metadata API #10441
Description
Currently, as highlighted in #6600, std.fs is very posix-based, which is harmful to cross-platform functionality. To improve the situation, I'm working on abstracting stat and chmod (maybe chown too) to a lowest-common-denominator, with the option to use more fine-grained platform-specific functionality if desired.
I'm making this issue so that nobody else works on this at the same time as myself, and wastes my or their time :)