fixing up the docker env

[philipsoutham]

• Locking down the containers by restricting all and explicitly allowing kernel capabilities.
• Making containers read_only when base image allows (some poorly built ones do not)
  • Also explicitly defining volumes where data should be stored/mutated.
• Making sure uid is not root when we can
• Defining configuration values in environment variables
• Taking the stuff from tiangolo/uvicorn-gunicorn-fastapi:python3.7 that makes it special and building our own image from the official python base image
• using the official redis base image
• adding tmpfs to fastapi
• removing exposed ports that didn't need to be exposed