internal/rosa: pass stage alongside state

This cleans up many function signatures.

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

internal/rosa/pcre2.go

@@ -4,12 +4,12 @@ import (
 	"hakurei.app/internal/pkg"
 )
 
-func (t Toolchain) newPCRE2(s *S) (pkg.Artifact, string) {
+func (t Toolchain) newPCRE2() (pkg.Artifact, string) {
 	const (
 		version  = "10.47"
 		checksum = "IbC24vVayju6nB9EhrBPSDexk22wDecdpyrjgC3nCZXkwTnUjq4CD2q5sopqu6CW"
 	)
-	return s.NewPackage(t, "pcre2", version, newFromGitHubRelease(
+	return t.NewPackage("pcre2", version, newFromGitHubRelease(
 		"PCRE2Project/pcre2",
 		"pcre2-"+version,
 		"pcre2-"+version+".tar.bz2",