feat: support out_dir in config

[CatBraaain]

dist-workspace.toml now supports package.out-dir.
Previously, for non-Rust projects, binaries were assumed to be placed directly under the root. With this change, build artifacts can be stored in an arbitrary folder.

Related issues:

• Generic builds: provide config for artifact subdir #874
• support specifying target dirs for generic/js builds #1335

[CatBraaain]

I named this field out_dir to match GenericBuildStep.out_dir, but if allowed, I personally think bin_dir would be more readable.

[CatBraaain]

@ashleygwilliams
This PR introduces a change that is very important for non-Rust projects.
Once this is merged, I’m planning to adopt it in my own project.
If possible, I’d really appreciate it if you could take a look at this with priority.
When you have time, I’d really appreciate a prioritized review.

Have a good day!

[mistydemeo]

Hi! Sorry, I haven't had the time to review this, but I'm going to try to get to it soon.

[mistydemeo]

I think it would make sense to have an assignment that checks if package.out_dir is defined, and branch based on that. So, up earlier in the file, you might do something like:

let out_dir = if let Some(dir) = package.out_dir {
  package.package_root.join(dir)
} else {
  package.package_root.clone()
};

And then pass that out_dir here.

[CatBraaain]

Thanks for the reviewing. I’ve updated the code to assign out_dir to a variable and branch with if let Some(...) as recommended.