Upgrade or remove dependency on Redis package

[geordi]

Since Django 4.0, there's a Redis backend built in. Also, current django-redis-cache we're using for Redis only supports Django up to version 3.2 and latest development stalled in March 2022.

We can use django-redis that is actively developed. It supports newest version of Django and is still relevant even that Django supports Redis by itself.

The final option is to simply drop dependency on these packages and use just built-in Redis functionality of Django.

[geordi]

Fixed by @Kobzol in #486