universal-lock: deal with hashes (or lack there of) for some types of distributions

[BurntSushi]

Currently, a ResolvedDist does not always have a hash. This is a problem for the lock file where we'd ideally want hashes for at least direct URL dependencies. We currently also don't have hashes for Git or Path dependencies, but I think we probably don't want those. (Cargo doesn't use hashes for that case either.)

So I think we need to fix this:

uv/crates/uv-resolver/src/lock.rs

Lines 688 to 695 in e33ff95

	fn from_direct_dist(direct_dist: &DirectUrlBuiltDist) -> Wheel {
	Wheel {
	url: direct_dist.url.to_url(),
	// TODO: We want a hash for the artifact at the URL.
	hash: todo!(),
	filename: direct_dist.filename.clone(),
	}
	}

And this:

uv/crates/uv-resolver/src/lock.rs

Lines 601 to 607 in e33ff95

	fn from_direct_dist(direct_dist: &DirectUrlSourceDist) -> SourceDist {
	SourceDist {
	url: direct_dist.url.to_url(),
	// TODO: We want a hash for the artifact at the URL.
	hash: todo!(),
	}
	}

And then probably update the data structures so that hash isn't required for the git and path sources.