support microsoft entra id for authentication with azure cache for redis

[dimbleby]

support microsoft entra id for authentication with azure cache for redis

[bbrowning918]

channels_redis only passes along what each hosts entry is to the redis async client if it is a dictionary (ignoring the address or tuple shortcut).

Much of the headache comes from managing reauthentication, as otherwise they state to pass in the Object ID and the Entra token as username and password respectively.

Passing in a credential_provider that handles the token refresh should be a good start. I am unsure how to handle the required AUTH call to Redis itself. Perhaps health_check_interval or retry but that is deeper into redis-py than I am familiar with. Asking in redis-py itself might provide a better answer (I came up empty looking for Entra related things 😞).

channels_redis isn't quite the layer that is at fault here, but with the correct dictionary passed into hosts (for redis-py to use) everything should be happy.