Update dkan_metastore_form for better dev mode and security

[janette]

• update package.json > "react-scripts": "3.4.0",
• public/index.html > change to "app"
• index.js add default uuid for development > const uuid = window.drupalSettings ? window.drupalSettings.tempUUID : '1f2042ad-c513-4fcf-a933-cae6c6fd35e6';
• app.js > import axios from "axios";
• app.js set default state to null >const [identifier, setIdentifier] = useState(null);
• change from query param to just /uuid -- add new route -- add new function -- change use of uuid to use the tempUUID