Add noop storage backend

This is sometimes useful when an update gets stuck because of some
bug in backup logic.

Note that you cannot restore from this backend because nothing is
saved.

webadmin/src/views/settings.js

@@ -53,7 +53,8 @@ angular.module('Application').controller('SettingsController', ['$scope', '$loca
     $scope.storageProvider = [
         { name: 'Amazon S3', value: 's3' },
         { name: 'Filesystem', value: 'filesystem' },
-        { name: 'Minio', value: 'minio' }
+        { name: 'Minio', value: 'minio' },
+        { name: 'No-op (Only for testing)', value: 'noop' }
     ];
 
     $scope.retentionTimes = [