`.env` file support issue tracker

This is a follow-up of [dotenv support pr](https://github.com/nodejs/node/pull/48890) to track the development process, and answer some questions that require a general discussion for making the decision to implement them. Todos: - [x] Precisely define the syntax of `.env` files, and consider a better format not based on ini - [x] Supporting absolute paths for .env file https://github.com/nodejs/node/pull/51425 - [x] Should we support multiple `--env-file` through the CLI? (cc @GeoffreyBooth) https://github.com/nodejs/node/pull/49542 - [x] Support multi-line values https://github.com/nodejs/node/pull/51289 - [x] Follow up after @tniessen's PR has landed to main https://github.com/nodejs/node/pull/49213 - [x] Should we add a programmatic API? If yes, what would be the use-case? (cc @cjihrig) https://github.com/nodejs/node/pull/51476 Questions: - [x] ~~Should we merge NODE_OPTIONS if both environment variable and .env version exist? Currently, we prefer environment variable over .env configuration.~~ (cc @ljharb) https://github.com/nodejs/node/pull/49217 - [x] Should we throw if `.env` file does not exist? We currently follow the default behavior of `dotenv` package and do not throw. (cc @MoLow) Please feel free to edit this issue in case there are more questions that needs to be answered. cc @nodejs/tsc