Make redis configurable and bump channels version

[mldulaney]

This provides the config option for setting the redis host.

[dreinhold]

The bump in channels is causing the CI build to fail :
error message

The conflict is caused by:
    The user requested asgiref==3.3.4
    channels 3.0.5 depends on asgiref<4 and >=3.5.0
ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

[mldulaney]

oh, okay, it worked locally, I'll poke it when I get home.

[mldulaney]

aight, that is done.

[dreinhold]

Okay cool it does build, did you see my note asking if you could update the settings to make them look for environment variables also, so it would work in docker?

Sorry was waiting for that before merging .