Respect "rpmmod" PURL qualifier (#4314)

Red Hat purls the RPM modularity info in a query param in the PURLs in
their vulnerability data. It would be nice if Syft respected this
qualifier so that Grype can use it when a Red Hat purl is passed.

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

syft/internal/fileresolver/metadata_test.go

@@ -4,9 +4,10 @@ import (
 	"os"
 	"testing"
 
-	"github.com/anchore/stereoscope/pkg/file"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/anchore/stereoscope/pkg/file"
 )
 
 func TestFileMetadataFromPath(t *testing.T) {