Websocket async implementation must use pure async lib when available

[rakshith91]

Currently, we use websocket-client library which does not have a pure async implementation

websockets has one, but it does not support http proxy python-websockets/websockets#364

When possible use a pure async library

[hansmbakker]

aiohttp.ClientSession.ws_connect with aiohttp.ClientWebSocketResponse works quite well.

It has support for async, proxy, ssl settings, etc.

[annatisch]

Thanks for this input @hansmbakker!
FYI @l0lawrence, @kashifkhan, @swathipil - we should look at this soon as we will need an async story for EH before GA.

[kashifkhan]

Thank you very much @hansmbakker for sharing about the websocket client in aiohttp , this worked out perfectly for us :)