Made a lot of changes around the notifcations to support the custom app name

also started on the welcome email ##1456

src/Ombi.DependencyInjection/IocExtensions.cs

@@ -144,6 +144,7 @@ namespace Ombi.DependencyInjection
             services.AddTransient<IRadarrCacher, RadarrCacher>();
             services.AddTransient<IOmbiAutomaticUpdater, OmbiAutomaticUpdater>();
             services.AddTransient<IPlexUserImporter, PlexUserImporter>();
+            services.AddTransient<IWelcomeEmail, WelcomeEmail>();
         }
     }
 }