internal/rosa: pass stage alongside state

This cleans up many function signatures.

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

internal/rosa/unzip.go

@@ -6,12 +6,12 @@ import (
 	"hakurei.app/internal/pkg"
 )
 
-func (t Toolchain) newUnzip(s *S) (pkg.Artifact, string) {
+func (t Toolchain) newUnzip() (pkg.Artifact, string) {
 	const (
 		version  = "6.0"
 		checksum = "fcqjB1IOVRNJ16K5gTGEDt3zCJDVBc7EDSra9w3H93stqkNwH1vaPQs_QGOpQZu1"
 	)
-	return s.New(t, "unzip-"+version, 0, s.AppendPresets(t, nil,
+	return t.New("unzip-"+version, 0, t.Append(nil,
 		Make,
 		Coreutils,
 	), nil, nil, `
@@ -21,7 +21,7 @@ make -f unix/Makefile generic1
 
 mkdir -p /work/system/bin/
 mv unzip /work/system/bin/
-`, pkg.Path(AbsUsrSrc.Append("unzip"), true, s.NewPatchedSource(t,
+`, pkg.Path(AbsUsrSrc.Append("unzip"), true, t.NewPatchedSource(
 		"unzip", version, newTar(
 			"https://downloads.sourceforge.net/project/infozip/"+
 				"UnZip%206.x%20%28latest%29/UnZip%20"+version+"/"+