feat: add SendGrid Email provider (#2865)

* feat: add support for email provider send grid

* feat: rename send grid to sendgrid

* feat: rename send grid to sendgrid

* feat: change logo url of send grid

email/sendgrid.go

@@ -0,0 +1,37 @@
+// Copyright 2024 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 email
+
+import (
+	"github.com/sendgrid/sendgrid-go"
+	"github.com/sendgrid/sendgrid-go/helpers/mail"
+)
+
+type SendgridEmailProvider struct {
+	ApiKey string
+}
+
+func NewSendgridEmailProvider(apiKey string) *SendgridEmailProvider {
+	return &SendgridEmailProvider{ApiKey: apiKey}
+}
+
+func (s *SendgridEmailProvider) Send(fromAddress string, fromName, toAddress string, subject string, content string) error {
+	from := mail.NewEmail(fromName, fromAddress)
+	to := mail.NewEmail("", toAddress)
+	message := mail.NewSingleEmail(from, subject, to, "", content)
+	client := sendgrid.NewSendClient(s.ApiKey)
+	_, err := client.Send(message)
+	return err
+}