Add Docker build and installation support

[echuraev]

Introduced docker configuration to build official docker image and then use it to installation on user servers.

[echuraev]

@ReturnFI Thank you for the awesome repo.

I wanted to use Blitz from docker container to have opportunity to easily install and remove it on my server. But I didn't find a way how to do that. So, I decided to try to do such configuration.

This is an initial setup. I suppose that the image should be built by the owners of the Blitz and uploaded to the DockerHub. After that users will be able to install it with the similar docker file:

services:
  mongodb:
    image: mongo:8.0
    container_name: mongodb
    restart: unless-stopped
    network_mode: "host"
    volumes:
      - mongodb_data:/data/db

  blitz:
    image: blitz:latest
    container_name: blitz
    restart: unless-stopped
    network_mode: "host"
    cap_add:
      - NET_ADMIN   # required for WARP (wireguard) and IP limiting (iptables)
    env_file: docker/.env
    volumes:
      - blitz_data:/blitz-data
    depends_on:
      - mongodb

volumes:
  blitz_data:
  mongodb_data:

Please take a look. I'll appreciate for any feedback and help with adding docker support.

[echuraev]

Also see that the same request was in issue #246.

[ReturnFI]

Thank you for your contribution.❤️

Currently, internet access in Iran is difficult, and I am unable to review your PR.
I will definitely review it after this war ends and Iran is free🕊🕊.
Thank you.❤️

[echuraev]

Thank you for your answer. I completely understand the situation. Please take care of yourself and stay safe. I truly wish you and everyone around you good health, safety, and strength during this difficult time. I hope the war ends soon and that peace comes as quickly as possible.🕊️