Move file backend to its own service (#9435)

* Move file backend to its own service

* Moving utils/inbucket to mailservice package

app/admin.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
+	"github.com/mattermost/mattermost-server/services/mailservice"
 	"github.com/mattermost/mattermost-server/utils"
 )
 
@@ -242,7 +243,7 @@ func (a *App) TestEmail(userId string, cfg *model.Config) *model.AppError {
 	} else {
 		T := utils.GetUserTranslations(user.Locale)
 		license := a.License()
-		if err := utils.SendMailUsingConfig(user.Email, T("api.admin.test_email.subject"), T("api.admin.test_email.body"), cfg, license != nil && *license.Features.Compliance); err != nil {
+		if err := mailservice.SendMailUsingConfig(user.Email, T("api.admin.test_email.subject"), T("api.admin.test_email.body"), cfg, license != nil && *license.Features.Compliance); err != nil {
 			return model.NewAppError("testEmail", "app.admin.test_email.failure", map[string]interface{}{"Error": err.Error()}, "", http.StatusInternalServerError)
 		}
 	}

app/email.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
+	"github.com/mattermost/mattermost-server/services/mailservice"
 	"github.com/mattermost/mattermost-server/utils"
 )
 
@@ -402,5 +403,5 @@ func (a *App) SendDeactivateAccountEmail(email string, locale, siteURL string) *
 
 func (a *App) SendMail(to, subject, htmlBody string) *model.AppError {
 	license := a.License()
-	return utils.SendMailUsingConfig(to, subject, htmlBody, a.Config(), license != nil && *license.Features.Compliance)
+	return mailservice.SendMailUsingConfig(to, subject, htmlBody, a.Config(), license != nil && *license.Features.Compliance)
 }

app/file.go

@@ -29,6 +29,7 @@ import (
 	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/plugin"
+	"github.com/mattermost/mattermost-server/services/filesstore"
 	"github.com/mattermost/mattermost-server/utils"
 )
 
@@ -58,9 +59,9 @@ const (
 	IMAGE_PREVIEW_PIXEL_WIDTH    = 1920
 )
 
-func (a *App) FileBackend() (utils.FileBackend, *model.AppError) {
+func (a *App) FileBackend() (filesstore.FileBackend, *model.AppError) {
 	license := a.License()
-	return utils.NewFileBackend(&a.Config().FileSettings, license != nil && *license.Features.Compliance)
+	return filesstore.NewFileBackend(&a.Config().FileSettings, license != nil && *license.Features.Compliance)
 }
 
 func (a *App) ReadFile(path string) ([]byte, *model.AppError) {