WebSocket Open Connection - add parameter for protocols

[Petra Vanickova]

Many of the websocket clients support a list of protocols in their constructor (e.g. described here https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_client_applications ).

Even though this could be implemented by setting Sec-WebSocket-Protocol header with HTTP Header Manaager, it would improve usability to set the protocols as a parameter of the WebSocket Open Connection .