WebSocketSharp does not look like properly maintained

[eyalpd-lmt]

Maybe worth investigating mentioning this/removing from the repo.

sta/websocket-sharp#748
sta/websocket-sharp#542 (comment)
dotnet/docs#43001

[Mazyod]

Good call, I think there have been much better alternatives in recent years. Will work on replacing the default and perhaps remove websocket-sharp.

[Mazyod]

Added explicit support to NativeWebSocket, which is recommended for Unity projects.