gui: Add one-off notifications that need to be acked

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3254

gui/default/syncthing/core/notificationDirective.js

@@ -0,0 +1,21 @@
+angular.module('syncthing.core')
+    .directive('notification', function () {
+        return {
+            restrict: 'E',
+            scope: true,
+            transclude: true,
+            template: '<div class="row" ng-if="visible()"><div class="col-md-12" ng-transclude></div></div>',
+            link: function (scope, elm, attrs) {
+                scope.visible = function () {
+                    return scope.config.options.unackedNotificationIDs.indexOf(attrs.id) > -1;
+                }
+                scope.dismiss = function () {
+                    var idx = scope.config.options.unackedNotificationIDs.indexOf(attrs.id);
+                    if (idx > -1) {
+                        scope.config.options.unackedNotificationIDs.splice(idx, 1);
+                        scope.saveConfig();
+                    }
+                }
+            }
+        };
+});

gui/default/syncthing/core/notifications.html

@@ -0,0 +1,16 @@
+<!--
+<notification id='exampleNotification'>
+  <div class="panel panel-warning">
+    <div class="panel-heading"><h3 class="panel-title"><span class="fa fa-exclamation-circle"></span><span translate>Notice</span></h3></div>
+    <div class="panel-body">
+      <p translate>This is an example notification. ID of the notification should be appended to Options.UnackedNotificationIDs of the config.</p>
+    </div>
+    <div class="panel-footer">
+      <button type="button" class="btn btn-sm btn-default pull-right" ng-click="dismiss()">
+        <span class="fa fa-check"></span>&nbsp;<span translate>OK</span>
+      </button>
+      <div class="clearfix"></div>
+    </div>
+  </div>
+</notification>
+-->