Websocket CloseCode Empty/Status is ambiguous

[fuchsnj]

The CloseCode::Empty and CloseCode::Status are basically the same code.

According to the RFC, if a client sends no close code (CloseCode::Empty) this is equivalent to 1005 (CloseCode::Status). This can be confusing since it might not be obvious which one of these values you should check against.

I suggest removing CloseCode::Empty and using an Option::None instead.
I would also recommend changing CloseCode::Status to CloseCode::NoStatus to reflect what it actually means.

These are both breaking changes, but if you like them I can make a PR for this.

[fuchsnj]

After thinking more... it might make sense to get rid of both of these, and replace them with Option::None

[fafhrd91]

let's use Option::None, i think it makes sense.