Make repo installable from offline media

[dhruvkb]

Description

Openverse should be easy to install from offline media like a flash drive. This will make it extremely easy to set up Openverse for contributors by carrying the repository on a flash drive to various coding events. This requires multiple things:

The repo should be copyable onto a flash drive that can support multiple Unix-like operating systems (with support for file system permissions etc.).

We should have just recipes to

• download the Docker images offline
• load the Docker images from offline .tar.gz files

We should have commands and just recipes to ensure that the repo can be cleaned of all untracked files like environment variables and secrets.

Additional context

This issue was identified at contributor day.