Make better use of i18n (#20096)

* Prototyping

* Start work on creating offsets

* Modify tests

* Start prototyping with actual MPH

* Twiddle around

* Twiddle around comments

* Convert templates

* Fix external languages

* Fix latest translation

* Fix some test

* Tidy up code

* Use simple map

* go mod tidy

* Move back to data structure

- Uses less memory by creating for each language a map.

* Apply suggestions from code review

Co-authored-by: delvh <dev.lh@web.de>

* Add some comments

* Fix tests

* Try to fix tests

* Use en-US as defacto fallback

* Use correct slices

* refactor (#4)

* Remove TryTr, add log for missing translation key

* Refactor i18n

- Separate dev and production locale stores.
- Allow for live-reloading in dev mode.

Co-authored-by: zeripath <art27@cantab.net>

* Fix live-reloading & check for errors

* Make linter happy

* live-reload with periodic check (#5)

* Fix tests

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>

services/mailer/mail.go

@@ -75,8 +75,8 @@ func sendUserMail(language string, u *user_model.User, tpl base.TplName, code, s
 	locale := translation.NewLocale(language)
 	data := map[string]interface{}{
 		"DisplayName":       u.DisplayName(),
-		"ActiveCodeLives":   timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, language),
-		"ResetPwdCodeLives": timeutil.MinutesToFriendly(setting.Service.ResetPwdCodeLives, language),
+		"ActiveCodeLives":   timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, locale),
+		"ResetPwdCodeLives": timeutil.MinutesToFriendly(setting.Service.ResetPwdCodeLives, locale),
 		"Code":              code,
 		"Language":          locale.Language(),
 		// helper
@@ -126,7 +126,7 @@ func SendActivateEmailMail(u *user_model.User, email *user_model.EmailAddress) {
 	locale := translation.NewLocale(u.Language)
 	data := map[string]interface{}{
 		"DisplayName":     u.DisplayName(),
-		"ActiveCodeLives": timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, locale.Language()),
+		"ActiveCodeLives": timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, locale),
 		"Code":            u.GenerateEmailActivateCode(email.Email),
 		"Email":           email.Email,
 		"Language":        locale.Language(),