New: Added silent notification option to telegram

(cherry picked from commit 9e392977b9f66be37c1fd6938c0b051c362ddb42)

src/NzbDrone.Core/Notifications/Telegram/TelegramService.cs

@@ -37,6 +37,7 @@ namespace NzbDrone.Core.Notifications.Telegram
             request.AddParameter("chat_id", settings.ChatId);
             request.AddParameter("parse_mode", "HTML");
             request.AddParameter("text", text);
+            request.AddParameter("disable_notification", settings.SendSilently);
 
             client.ExecuteAndValidate(request);
         }

src/NzbDrone.Core/Notifications/Telegram/TelegramSettings.cs

@@ -24,7 +24,8 @@ namespace NzbDrone.Core.Notifications.Telegram
         [FieldDefinition(1, Label = "Chat ID", HelpLink = "http://stackoverflow.com/a/37396871/882971", HelpText = "You must start a conversation with the bot or add it to your group to receive messages")]
         public string ChatId { get; set; }
 
-        public bool IsValid => !string.IsNullOrWhiteSpace(ChatId) && !string.IsNullOrWhiteSpace(BotToken);
+        [FieldDefinition(2, Label = "Send Silently", Type = FieldType.Checkbox, HelpText = "Sends the message silently. Users will receive a notification with no sound")]
+        public bool SendSilently { get; set; }
 
         public NzbDroneValidationResult Validate()
         {