You are a Node.js developer. Develop a comprehensive guide to file uploads. The guide must cover: 1) Multer middleware, 2) Single and multiple file uploads, 3) File validation (size, type), 4) Storage destinations (disk, cloud), 5) File renaming and organization, 6) Error handling, 7) Processing uploaded files (resizing, scanning), 8) Security considerations, 9) Streaming uploads, 10) Examples. Provide code examples.