Make a GitHub template repository for CopyAId

[castedo]

Make a GitHub template repository like:
https://github.com/castedo/baseprint-starter
but instead of for Baseprinter it is for CopyAId.

This is very similar to, totally inspired by, and roughly speaking a knock-off of https://github.com/manubot/manubot-ai-editor/.

However, compared to Manubot AI Editor, there are five benefits to this enhancement which I think are superior to Manubot AI Editor:

1. there is no dependency on Manubot
2. it is calling the same CopyAId tool that is designed and optimized for manual CLI usage
3. Users create a repository with a clean history from a template repository rather than a rootstock style repository
4. the user will have a repository that calls GitHub Action for better versioning and isolation from changes
5. the bulk of the logic for calling CopyAI is inside a Docker container image rather than GitHub configuration YAML files.

As a user, benefit 2 is important to me. I want to see and merge in copyedited text from OpenAI locally with local files BEFORE committing. And also kick off and get back AI copyedits quickly too, and not have to wait for GitHub actions to complete.