fix: Support Telegram Notification provider (#2225)

* fear: support telegram provider

* fix: fix telegram logo

* fix: fix telegram bot package

* Update telegram.go

* Update notification.go

---------

Co-authored-by: hsluoyz <hsluoyz@qq.com>

object/notification.go

@@ -0,0 +1,42 @@
+// Copyright 2023 The Casdoor Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package object
+
+import (
+	"context"
+
+	"github.com/casdoor/casdoor/notification"
+	"github.com/nikoksr/notify"
+)
+
+func getNotificationClient(provider *Provider) (notify.Notifier, error) {
+	var client notify.Notifier
+	client, err := notification.GetNotificationProvider(provider.Type, provider.AppId, provider.Receiver)
+	if err != nil {
+		return nil, err
+	}
+
+	return client, nil
+}
+
+func SendNotification(provider *Provider, content string) error {
+	client, err := getNotificationClient(provider)
+	if err != nil {
+		return err
+	}
+
+	err = client.Send(context.Background(), "", content)
+	return err
+}