Use cases
- https://stackoverflow.com/questions/54220775/how-to-use-variable-substitution-in-frontend-js-applications-like-backend-applic/54271114#54271114
- https://stackoverflow.com/questions/66883900/is-it-possible-to-use-a-react-server-enviroment-variables-into-frontend-at-clien/66915031#66915031
- https://stackoverflow.com/questions/57452441/what-code-repository-should-the-dockerfile-get-committed-to/57550066#57550066
- https://stackoverflow.com/questions/67789512/how-to-check-node-js-environment-variables-from-kubernetes-pod/67798027#67798027