PLT-1800 Load server side locale from the config.json (#3092)

* PLT-1800 Load server side locale from the config.json

* Add support for locales with country specifics

* Fix localization on served locale file as plain/text

web/web_test.go

@@ -21,7 +21,7 @@ var URL string
 func Setup() {
 	if api.Srv == nil {
 		utils.LoadConfig("config.json")
-		utils.InitTranslations()
+		utils.InitTranslations(utils.Cfg.LocalizationSettings)
 		api.NewServer()
 		api.StartServer()
 		api.InitApi()