Asyncio backend: SSL doesn't work

[Lorak-mmk]

When using AsyncioConnection it's not possible to connect to Scylla using SSL - the connection hangs and eventually timeouts.
The issue is that asyncio methods like sock_sendall don't work with SSLSocket - they explicitly check the type of the socket here (definition of this function)
Another issue is that this exception is swallowed somewhere, so we don't see it in the terminal - there probably should be a catch-all block that prints the exception.

The solution would probably be to rework AsyncioConnection.__init__ and other methods a bit to use https://docs.python.org/3/library/asyncio-stream.html#asyncio.open_connection