Enhancement proposal, websocket client

[dusanx]

Crow is amazing, thank you for the effort. There is one missing bit, and I am aware it is not completely in line with rest of the project, but it would greatly round up what Crow can do: I would love to see websocket client support with the same great syntax that Crow already has. Alternative to having proper websocket client in C++ is to use boost, which is sub-optimal.

Websocket client code should very much look like https://crowcpp.org/master/guides/websockets/, only with the ability to connect to websocket server. Additional plus would be ability to retry connection if it breaks.

I am willing to put a bounty on this one so please let me know what is needed on my side.