[ie/youtube] Add a PO Token Provider Framework (#12840)

https://github.com/yt-dlp/yt-dlp/tree/master/yt_dlp/extractor/youtube/pot/README.md

Authored by: coletdjnz

yt_dlp/networking/_websockets.py

@@ -11,8 +11,8 @@ from ._helper import (
     create_connection,
     create_socks_proxy_socket,
     make_socks_proxy_opts,
-    select_proxy,
 )
+from ..utils.networking import select_proxy
 from .common import Features, Response, register_rh
 from .exceptions import (
     CertificateVerifyError,