Add JavaScript Version of Plugins Quickstart

[brianpetro]

This pull request adds a JavaScript implementation to the plugin-quickstart repository. The goal is to provide users with an alternative language option for setting up and running the plugin. This PR includes the following changes:

• A new main.js file containing the JavaScript implementation using Express.js and cors.
• An update to the README.md file to include setup instructions for both the Python and JavaScript versions of the plugin.
• A new package.json file to manage the JavaScript dependencies.