nixos/vaultwarden: drop outdated ownership requirements for environmentFile (#304825)

        Additional environment file as defined in {manpage}`systemd.exec(5)`.

        Secrets like {env}`ADMIN_TOKEN` and {env}`SMTP_PASSWORD`

        may be passed to the service without adding them to the world-readable Nix store.

        should be passed to the service without adding them to the world-readable Nix store.

        Note that this file needs to be available on the host on which

        `vaultwarden` is running.

        Note that this file needs to be available on the host on which `vaultwarden` is running.

        As a concrete example, to make the Admin UI available

        (from which new users can be invited initially),

        As a concrete example, to make the Admin UI available (from which new users can be invited initially),

        the secret {env}`ADMIN_TOKEN` needs to be defined as described

        [here](https://github.com/dani-garcia/vaultwarden/wiki/Enabling-admin-page).

        Setting `environmentFile` to `/var/lib/vaultwarden.env`

        and ensuring permissions with e.g.

        `chown vaultwarden:vaultwarden /var/lib/vaultwarden.env`

        (the `vaultwarden` user will only exist after activating with

        `enable = true;` before this), we can set the contents of the file to have

        contents such as:

        [here](https://github.com/dani-garcia/vaultwarden/wiki/Enabling-admin-page):

        ```

        # Admin secret token, see