CLI Tool for hierarchical environment variable management

- Compile a resulting set of environment variables from a hierarchical list of `<name>.env` files. - Dependencies can form a tree or DAG (directed acyclic graph). - Smart environment selection via builtin FZF (fuzzy find). - Side-by-side edit of trees for easy comparison. - [direnv](https://direnv.net/) integration - [JetBrains](https://www.jetbrains.com/) integration via [EnvFile](https://plugins.jetbrains.com/plugin/7861-envfile) plugin.