osbuild: remove dead code

The helper functions were never used, we should aim to use the
osbuild types just as regular structs for serialization purposes.

Signed-off-by: Tom Gundersen <teg@jklm.no>

internal/blueprint/blueprint_test.go

@@ -1,9 +1,10 @@
 package blueprint
 
 import (
+	"testing"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"testing"
 )
 
 func TestDeepCopy(t *testing.T) {