Decouple emailservice from app package (#17827)

* decouple emailservice from app package

* fix some escaped errors

* move email package under app directory

* fix i18n

* reflect review comments

app/email/utils.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package email
+
+import (
+	"github.com/mattermost/mattermost-server/v5/shared/mail"
+	"github.com/mattermost/mattermost-server/v5/utils"
+)
+
+func (es *Service) mailServiceConfig() *mail.SMTPConfig {
+	emailSettings := es.config().EmailSettings
+	hostname := utils.GetHostnameFromSiteURL(*es.config().ServiceSettings.SiteURL)
+	cfg := mail.SMTPConfig{
+		Hostname:                          hostname,
+		ConnectionSecurity:                *emailSettings.ConnectionSecurity,
+		SkipServerCertificateVerification: *emailSettings.SkipServerCertificateVerification,
+		ServerName:                        *emailSettings.SMTPServer,
+		Server:                            *emailSettings.SMTPServer,
+		Port:                              *emailSettings.SMTPPort,
+		ServerTimeout:                     *emailSettings.SMTPServerTimeout,
+		Username:                          *emailSettings.SMTPUsername,
+		Password:                          *emailSettings.SMTPPassword,
+		EnableSMTPAuth:                    *emailSettings.EnableSMTPAuth,
+		SendEmailNotifications:            *emailSettings.SendEmailNotifications,
+		FeedbackName:                      *emailSettings.FeedbackName,
+		FeedbackEmail:                     *emailSettings.FeedbackEmail,
+		ReplyToAddress:                    *emailSettings.ReplyToAddress,
+	}
+	return &cfg
+}