Move documentation about running data mungers from PR descriptions into repo

[AetherUnbound]

There are a number of PR descriptions that have excellent guides on how to run various data munging scripts and upload them in production. This information is pretty vital and should probably exist within the repo. Case in point: #74

[ambertests]

Hi, I'd love to contribute to this project and this seems like it could be a good first issue to take on.

[AetherUnbound]

Hi @ambertests, thanks for reaching out! 😄 We mostly want to move that PR documentation into separate markdown files within the repo. Alternatively we could add them to the docstrings for the module and set up Sphinx/GitHub Pages documentation, but that's a lot more complex 😅 Up to whatever you're comfortable with! I'll assign you, let us know if you run into any trouble 🙂

[AetherUnbound]

The PRs that could use documentation:
#42
#39
#50
#74
#51
#52
#73
#89
#99