Now loading barcode format from env with overwrite via query param

ref #13

src/config.ts

@@ -4,7 +4,8 @@ configDotenv();
 export const config = {
     internal_port: parseInt(process.env.APP_PORT) || 4010,
     development: process.env.NODE_ENV === "production",
-    version: process.env.VERSION || require('../package.json').version
+    version: process.env.VERSION || require('../package.json').version,
+    codeformat: process.env.CODEFORMAT || "qrcode"
 }
 let errors = 0
 if (typeof config.internal_port !== "number") {