Documentation on how to review a Copilot authored PR

We can now add Copilot to an issue and it execute the tasks identified. When it has completed it submits a PR for review. Perhaps the easiest way to review these changes in isolation is to use CodeSpaces. We need to document how to do that. Below is a summary of the steps. Write a full guide on how to review Copilot PRs.

- Open the PR and start the review
- Click "Review in codespace"
- Install az cli
- Build Innovation Engine with `make build-ie`
- Run tests