Exit with code 1 (error) if wizard failed. (#96)

* Exit with code 1 (error) if wizard failed.
Should prevent error code 0 after
`creation failed: failed to create database (are you not running as root?).`
and similar errors.

* Switch error messages from stdin to stderr for init_wizard

server/src/main.rs

@@ -236,7 +236,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     match opt.command {
         Command::New { opts } => {
             if let Err(e) = initialize::init_wizard(&conf, opts) {
-                println!("{}: {}.", "creation failed".red(), e);
+                eprintln!("{}: {}.", "creation failed".red(), e);
+                std::process::exit(1);
             }
         },
         Command::Uninstall { interface } => uninstall(&interface, &conf, opt.network)?,