Apply icinga form style to remaining form classes

application/controllers/GroupController.php

@@ -46,7 +46,7 @@ class GroupController extends AuthBackendController
         }
 
         $this->view->backendSelection = new Form();
-        $this->view->backendSelection->setAttrib('class', 'backend-selection');
+        $this->view->backendSelection->setAttrib('class', 'backend-selection icinga-controls');
         $this->view->backendSelection->setUidDisabled();
         $this->view->backendSelection->setMethod('GET');
         $this->view->backendSelection->setTokenDisabled();

application/forms/Announcement/AnnouncementForm.php

@@ -92,6 +92,7 @@ class AnnouncementForm extends RepositoryForm
     {
         $this->setTitle(sprintf($this->translate('Remove announcement %s?'), $this->getIdentifier()));
         $this->setSubmitLabel($this->translate('Yes'));
+        $this->setAttrib('class', 'icinga-controls');
     }
 
     /**

application/forms/Config/User/UserForm.php

@@ -114,6 +114,7 @@ class UserForm extends RepositoryForm
     {
         $this->setTitle(sprintf($this->translate('Remove user %s?'), $this->getIdentifier()));
         $this->setSubmitLabel($this->translate('Yes'));
+        $this->setAttrib('class', 'icinga-controls');
     }
 
     /**

application/forms/Config/UserGroup/UserGroupForm.php

@@ -64,6 +64,7 @@ class UserGroupForm extends RepositoryForm
             . ' have their membership cleared automatically.'
         ));
         $this->setSubmitLabel($this->translate('Yes'));
+        $this->setAttrib('class', 'icinga-forms icinga-controls');
     }
 
     /**

application/forms/ConfirmRemovalForm.php

@@ -10,6 +10,8 @@ use Icinga\Web\Form;
  */
 class ConfirmRemovalForm extends Form
 {
+    const DEFAULT_CLASSES = 'icinga-controls';
+
     /**
      * {@inheritdoc}
      */