Extracting i18n functionality to i18n core library (#16914)

* extracting i18n functionality to i18n core library

* Removing utils.T

* Adding documentation and changing one function name for better explanation

* Changing other missing utils.T

* Adding license string

* Renaming corelibs to pkg

* Renaming corelibs to pkg (moving directory)

* Renaming from pkg to shared

* Fixing bodyPage.Html casing

* Fixing merges

* Fixing merge problem

* Fixing tests

cmd/mattermost/commands/config.go

@@ -17,6 +17,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/config"
 	"github.com/mattermost/mattermost-server/v5/mlog"
 	"github.com/mattermost/mattermost-server/v5/model"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
@@ -106,7 +107,7 @@ func init() {
 
 func configValidateCmdF(command *cobra.Command, args []string) error {
 	utils.TranslationsPreInit()
-	model.AppErrorInit(utils.T)
+	model.AppErrorInit(i18n.T)
 
 	_, err := getConfigStore(command)
 	if err != nil {

cmd/mattermost/commands/init.go

@@ -9,6 +9,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/app"
 	"github.com/mattermost/mattermost-server/v5/config"
 	"github.com/mattermost/mattermost-server/v5/model"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
@@ -37,7 +38,7 @@ func initDBCommandContext(configDSN string, readOnlyConfigStore bool) (*app.App,
 	if err := utils.TranslationsPreInit(); err != nil {
 		return nil, err
 	}
-	model.AppErrorInit(utils.T)
+	model.AppErrorInit(i18n.T)
 
 	s, err := app.NewServer(
 		app.Config(configDSN, false, readOnlyConfigStore, nil),

cmd/mattermost/commands/permissions.go

@@ -11,7 +11,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/mattermost/mattermost-server/v5/audit"
-	"github.com/mattermost/mattermost-server/v5/utils"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 )
 
 var PermissionsCmd = &cobra.Command{
@@ -102,7 +102,7 @@ func exportPermissionsCmdF(command *cobra.Command, args []string) error {
 	defer a.Srv().Shutdown()
 
 	if license := a.Srv().License(); license == nil {
-		return errors.New(utils.T("cli.license.critical"))
+		return errors.New(i18n.T("cli.license.critical"))
 	}
 
 	if err = a.ExportPermissions(os.Stdout); err != nil {
@@ -123,7 +123,7 @@ func importPermissionsCmdF(command *cobra.Command, args []string) error {
 	defer a.Srv().Shutdown()
 
 	if license := a.Srv().License(); license == nil {
-		return errors.New(utils.T("cli.license.critical"))
+		return errors.New(i18n.T("cli.license.critical"))
 	}
 
 	file, err := os.Open(args[0])

cmd/mattermost/commands/permissions_test.go

@@ -6,9 +6,8 @@ package commands
 import (
 	"testing"
 
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/stretchr/testify/assert"
-
-	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
 func TestPermissionsExport_rejectsUnlicensed(t *testing.T) {
@@ -16,7 +15,7 @@ func TestPermissionsExport_rejectsUnlicensed(t *testing.T) {
 	defer th.TearDown()
 
 	actual, _ := th.RunCommandWithOutput(t, "permissions", "export")
-	assert.Contains(t, actual, utils.T("cli.license.critical"))
+	assert.Contains(t, actual, i18n.T("cli.license.critical"))
 }
 
 func TestPermissionsImport_rejectsUnlicensed(t *testing.T) {
@@ -25,5 +24,5 @@ func TestPermissionsImport_rejectsUnlicensed(t *testing.T) {
 
 	actual, _ := th.RunCommandWithOutput(t, "permissions", "import")
 
-	assert.Contains(t, actual, utils.T("cli.license.critical"))
+	assert.Contains(t, actual, i18n.T("cli.license.critical"))
 }

cmd/mattermost/commands/test.go

@@ -15,7 +15,7 @@ import (
 
 	"github.com/mattermost/mattermost-server/v5/api4"
 	"github.com/mattermost/mattermost-server/v5/model"
-	"github.com/mattermost/mattermost-server/v5/utils"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/wsapi"
 )
 
@@ -52,7 +52,7 @@ func webClientTestsCmdF(command *cobra.Command, args []string) error {
 	}
 	defer a.Srv().Shutdown()
 
-	utils.InitTranslations(a.Config().LocalizationSettings)
+	i18n.InitTranslations(*a.Config().LocalizationSettings.DefaultServerLocale, *a.Config().LocalizationSettings.DefaultClientLocale)
 	serverErr := a.Srv().Start()
 	if serverErr != nil {
 		return serverErr
@@ -73,7 +73,7 @@ func serverForWebClientTestsCmdF(command *cobra.Command, args []string) error {
 	}
 	defer a.Srv().Shutdown()
 
-	utils.InitTranslations(a.Config().LocalizationSettings)
+	i18n.InitTranslations(*a.Config().LocalizationSettings.DefaultServerLocale, *a.Config().LocalizationSettings.DefaultClientLocale)
 	serverErr := a.Srv().Start()
 	if serverErr != nil {
 		return serverErr