Find command line way of adding files to S3

### Background

AWS GUI is always changing and kind of a pain to upload files to S3 through. There are command line options.

### What are the recommended next steps?

- Find a less annoying command line alternative to add S3 files to AWS.
- Potentially add it to the dockerfile.
- Update CONTRIBUTING.md for how to use it.

Some of @jashapiro 's suggestions to look into:

https://panic.com/transmit/
Something called Mountain Duck??

Edit: Apparently Josh's suggestions I put here are not command line but are GUIs, but supposedly better GUIs.

Start by reviewing the Dockerfile and CONTRIBUTING.md, then compare command-line options for adding files to S3 against the repository's workflow. Done means a CLI choice is agreed, any needed setup is addressed, and CONTRIBUTING.md explains how to use it.

Written by the indexing model from the issue text.