Update to 3.5.2 and .net core 2.1

Emby.Notifications/NotificationConfigurationFactory.cs

@@ -0,0 +1,21 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Model.Notifications;
+using System.Collections.Generic;
+
+namespace Emby.Notifications
+{
+    public class NotificationConfigurationFactory : IConfigurationFactory
+    {
+        public IEnumerable<ConfigurationStore> GetConfigurations()
+        {
+            return new ConfigurationStore[]
+            {
+                new ConfigurationStore
+                {
+                    Key = "notifications",
+                    ConfigurationType = typeof (NotificationOptions)
+                }
+            };
+        }
+    }
+}