rn, there are a lot of env vars that change how railway deploys stuff, eg the timeout between deploys, all the nixpacks vars, docker build kit, etc

This would help make config a lot easier, and with discoverability and reducing errors. Configuring them rn requires looking at docs, and finding the var, and then putting it into the env var page. Lots of the vars don't have great documentation, if at all, and u can easily make a typo, causing bugs.

Also, existing things like choosing which builder, and the start command could be migrated there.