Added config enable=true/false for extensions with default value as enabled closes #258

Signed-off-by: Alexei Dodon <adodon@cisco.com>

pkg/extensions/sync/sync.go

@@ -42,6 +42,7 @@ type Credentials struct {
 }
 
 type Config struct {
+	Enable          *bool
 	CredentialsFile string
 	Registries      []RegistryConfig
 }