Implement Structured `MemcachedError` for Enhanced Error Handling

[dkz2]

To ensure a more structured and intuitive error handling mechanism, we will be implementing a MemcachedError modeled after a pattern successfully utilized in the NIO world. The aim is to shift from relying on string description of errors to a more forward evolving type that retains as much relevant info as possible. The proposed MemcachedError structure will offer a Code type that represents high level error kinds coupled with a detailed description that includes the error message, cause, and exact source location.This approach will help developers quickly identify the nature and origin of the error.