dxp/issues#757: Add eslint and format the code

Test:

• Run npm run lint and make sure there is no error and the warnings there are fine to stay like that for now
• Compile the app with TS and make sure there is no TS error
• Run the app and make sure everything works as expected

src/components/factories/appFactory.tsx

+import React from "react";
+
 import { configService } from "@services";
 
 import PortalFactory from "./portalFactory";