feat: move to (io)redis

[piprett]

• Replace the @upstash/redis package with ioredis
• Rename environment variables to reflect the change
• Test it
• Document it
  • Usage with Upstash using redis URL with password included
  • Usage with redis-like databases
  • Example docker commands
• Fix CI

Currently unable to test it, getting weird TypeScript errors about not being able to find X

[vercel]

@Erb3 is attempting to deploy a commit to the Noodle Team on Vercel.

A member of the Team first needs to authorize it.