fix: make more server new command more robust

See coop-cloud/organising#163.

cli/internal/validate.go

@@ -41,3 +41,14 @@ func ValidateApp(c *cli.Context) config.App {
 
 	return app
 }
+
+// ValidateDomain ensures the domain name arg is valid.
+func ValidateDomain(c *cli.Context) string {
+	domainName := c.Args().First()
+
+	if domainName == "" {
+		ShowSubcommandHelpAndError(c, errors.New("no domain provided"))
+	}
+
+	return domainName
+}