internal/rosa: pass stage alongside state

This cleans up many function signatures.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/libtirpc.go

@@ -6,12 +6,12 @@ import (
 	"hakurei.app/internal/pkg"
 )
 
-func (t Toolchain) newLibtirpc(s *S) (pkg.Artifact, string) {
+func (t Toolchain) newLibtirpc() (pkg.Artifact, string) {
 	const (
 		version  = "1.3.7"
 		checksum = "nzFfu7LNvnSNiNAryD1vtnNWnU-Xqee8KqfXUKoBf5yjb5-dkeRkYuRijdCoYLof"
 	)
-	return s.NewPackage(t, "libtirpc", version, s.newTagRemote(t,
+	return t.NewPackage("libtirpc", version, t.newTagRemote(
 		"git://linux-nfs.org/~steved/libtirpc",
 		"libtirpc-"+
 			strings.Join(strings.SplitN(version, ".", 3), "-"),