add: gatsby-plugin-s3

## Info

- Plugin Name: `gatsby-plugin-s3`
- Plugin Repository: https://github.com/jariz/gatsby-plugin-s3/
- Plugin NPM page: https://www.npmjs.com/package/gatsby-plugin-s3

## Overview

Hi, I saw this repo and I think it quite fits with my situation.
I maintain `gatsby-plugin-s3`, [the recommended way to deploy to S3 in the gatsby docs itself](https://www.gatsbyjs.com/docs/how-to/previews-deploys-hosting/deploying-to-s3-cloudfront/).
I've largely declared the project as 'done' as it has generally achieved all the goals I personally set out for it, however, there's still [quite the backlog](https://github.com/jariz/gatsby-plugin-s3/issues) of additional features people would like to see.
Me and my co-maintainer have largely moved on from this project however.
People have suggested me to ask Gatsby itself to pick up the plugin, but because it is a direct concurrent of their own service, I very much doubt they're interested in picking it up. 😉

## Tasks

Contributor Tasks:
- [x] Move Repo to `gatsby-uc`
- [x] [Add `moonmeister` as a maintainer](https://docs.npmjs.com/transferring-a-package-from-a-user-account-to-another-user-account) on your npm package.

Admin Tasks:
- [ ] Move Code into `gatsby-uc/plugins` repo
- [ ] Update Readme in old repo to redirect folks to new location
- [ ] Archive old Repo
- [ ] Close any irrelevant PRs/Issues
- [ ] Move/Comment on still applicable issues
- [ ] Update Plugin with best practices
- [ ] Publish new version

Start with the checklist and the linked gatsby-plugin-s3 repository; verify the current repository and package state before taking on the migration. Done means the code is moved into gatsby-uc/plugins, the old repository is redirected and archived, relevant issues are handled, best practices are applied, and a new version is published.

Written by the indexing model from the issue text.