Update documentation for Github Action deployment

The documentation says that the tf-gha-deploy-infra.yml workflow will be available in the actions page to execute, but having recently worked with the repo it seems the tf-gha-deploy-infra.yml file is not present in the .github/workflows folder and has to be manually copied over from the infrastructure/terraform/github-actions folder.

Can we get either the documentation updated to include the manual copy step OR revert back to the previous version where tf-gha-deploy-infra.yml is available in the .github/workflows folder