[FEATURE]: Implement centralized Redis in production

[dgurns]

Is your feature request related to a problem? Please describe.
If we want to horizontally scale the API via a load balancer, we'll need to use a centralized Redis instance.

Describe the solution you'd like
Configure production to use a centralized Redis instance with password. Local and staging should continue using a local instance of Redis via docker-compose

Describe alternatives you've considered
One alternative is to vertically scale the backend, but I suspect horizontal scaling will be a better idea, due to probable limits on simultaneous websocket connections per server, cost, and redundancy.

Additional context