Fix redis integration

[Skycoder42]

Fixes #197.

This PR include 2 changes:

1. Wrap handle_message in create_task
2. Treat result of pubsub.get_message as dict instead of a tuple

[Benjamin-Loison]

As far as I understand your pull request makes WebSocket works, while it already works with the official instance. Is WebSocket still working on your unofficial instance? It is not despite your changes on mine, websocket_endpoint is not called despite collectionManager.itemManager.subscribeChanges:

uvicorn.access - INFO - XXX.XXX.XXX.XXX:0 - "POST /api/v1/collection/OQi24uZ0O6onZ1B66Ba16CZEpDCY35-G/item/subscription-ticket/ HTTP/1.1" 200
uvicorn.access - INFO - XXX.XXX.XXX.XXX:0 - "GET /api/v1/ws/XXXXXXXXXXXXXX_XXXXXXX_XXXXXXXXXXXX-XX-XXXX%3D/ HTTP/1.1" 404

Maybe my apache2:

        <Location "/">
            ProxyPass        http://localhost:8000/
            ProxyPreserveHost On
        </Location>

is to blame.

Personal notes: Benjamin_Loison/etesync_android/issues/5