Add note to login page when the configuration directory is missing

refs #7163
refs #7409

application/controllers/AuthenticationController.php

@@ -145,6 +145,8 @@ class AuthenticationController extends ActionController
         } catch (Exception $e) {
             $this->view->errorInfo = $e->getMessage();
         }
+
+        $this->view->configMissing = count($config->toArray()) === 0 && false === is_dir(Config::$configDir);
     }
 
     /**

application/views/scripts/authentication/login.phtml

@@ -15,5 +15,17 @@
    <?php endif ?>
    <?= $this->form ?>
    <div class="footer">Icinga Web 2 &copy; 2013-2014 Icinga Team</div>
+   <?php if ($configMissing): ?>
+   <div class="config-note"><?= sprintf(
+     t(
+       'You seem not to have Icinga Web 2 configured yet so it\'s not possible to log in without any defined '
+       . 'authentication method. Please define a authentication method by following the instructions in the'
+       . ' %1$sdocumentation%3$s or by using our %2$sweb-based installer%3$s.'
+     ),
+     '<a href="' . 'documention-link-here' . '" title="Icinga Web 2 Documentation">', // TODO: Documentation link
+     '<a href="' . $this->href('setup') . '" title="Icinga Web 2 Installer">',
+     '</a>'
+   ); ?></div>
+   <?php endif ?>
   </div>
  </div>

public/css/icinga/login.less

@@ -100,4 +100,13 @@
     text-align: center;
   }
 
+  div.config-note {
+    width: 50%;
+    padding: 1em;
+    margin: 5em auto 0;
+    text-align: center;
+    border-radius: 0.5em;
+    border: 2px solid coral;
+    background-color: beige;
+  }
 }