Create a Node.js application to upload files of various types to a MongoDB database using GridFS. Learn how to implement file storage with Multer, the GridFS storage engine, and gridfs-stream while utilizing the EJS template engine. Explore the process of setting up MongoDB, creating connections, implementing GridFS streams, and performing file operations such as uploading, retrieving, displaying, and deleting. Follow along with the step-by-step tutorial to build a functional file management system, including refactoring code for improved efficiency and handling different file types.