feat: refactor memory and disk storage classes, improve error handling and file size validation

[kalebalebachew]

• Refactored DiskStorage and MemoryStorage to use ES6 class syntax for better structure and maintainability.
• Introduced maxSize option in DiskStorage to enforce file size limits, with proper stream destruction on overflow.
• Promisified key file operations (randomBytes, unlink) to utilize async/await for cleaner and more readable code.
• Enhanced error handling in both file.stream and outStream to ensure robust error management.
• Improved variable declarations by using const for immutable values for better code consistency and clarity.

[kalebalebachew]

I think it should be fixed by now. let me know what to improve if u have one.