Websockets examples are not working with Python 3.10

[yyunikov]

Examples in 6_asyncio_websockets are not working with Python 3.10.

This can be observed with 2 issues:

1. New deprecation warnings appear as per https://docs.python.org/3/whatsnew/3.10.html [asyncio.get_event_loop()](https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.get_event_loop) now emits a deprecation warning if there is no running event loop.. Should be fixed by changing this code:

asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

to something like:

loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
loop.run_until_complete(start_server)
loop.run_forever()

2. Basic and advanced apps are not functioning anymore. Didn't look very close into the reason, but could be related.