internal/rosa/python: migrate setuptools to helper

This is much cleaner, and should be functionally equivalent.

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

internal/rosa/python.go

@@ -180,18 +180,12 @@ func (t Toolchain) newSetuptools() (pkg.Artifact, string) {
 		version  = "82.0.1"
 		checksum = "nznP46Tj539yqswtOrIM4nQgwLA1h-ApKX7z7ghazROCpyF5swtQGwsZoI93wkhc"
 	)
-	return t.New("setuptools-"+version, 0, t.AppendPresets(nil,
+	return t.NewPackage("setuptools", version, newFromGitHub(
-		Python,
-	), nil, nil, `
-pip3 install \
-	--no-index \
-	--prefix=/system \
-	--root=/work \
-	/usr/src/setuptools
-`, pkg.Path(AbsUsrSrc.Append("setuptools"), true, newFromGitHub(
 		"pypa/setuptools",
 		"v"+version, checksum,
-	))), version
+	), nil, &PipHelper{
+		BuildIsolation: true,
+	}), version
 }
 func init() {
 	artifactsM[Setuptools] = Metadata{