Consider removing cloudfront distributions from static websites in GitHub Pages

[marcoieni]

Some of our websites aren't visited so often that we need a cloudfront distribution in front of GitHub Pages.

1. List all the static websites using cloudfront distribution. Examples:
   • thanks:
     • change dns
     • disable cloudfront distribution
     • delete cloudfront distribution
     • don't invalidate thanks cloudfront distribution thanks#87
     • delete secrets from github actions CI
     • delete iam user
   • forge
     • change dns
     • disable cloudfront distribution
     • delete cloudfront distribution
     • don't invalidate cloudfront distribution rust-forge#988
     • delete secrets from github actions CI
     • delete iam user
2. For each website, delete the cloudfront distribution from simpleinfra and from the GitHub Actions workflow

Specific instructions

For thanks.rust-lang.org we listed the following instructions in #597. I'm not sure if they are up to date or correct, but I'm reporting them anyway:

• As an admin, change the GitHub settings (see Managing a custom domain for your GitHub Pages site)
• As an admin, change the DNS record to point to GitHub Pages
• As an admin, remove the CloudFront distribution once it is no longer used
• Replace the static-websites action as per the instructions above

Bonus points

• evaluate if we should close infra-team (view)

[marcoieni]

deleted thanks distribution with id E3URKC86CEGJWE.
I also deleted the thanks certificate with ID 86e48525-5ef9-4d6d-9689-a4e12d727ab4 in AWS Certificate Manager.