Hide localization text from frontend

[worthy7]

Since the localization files can get quite heavy, or may contain sensitive data not mean for all customers (like admin email text for example), I think that the LocalizationConfiguration should have a feature similar to the SettingsProvider, where you can decide if the localization text is shown on the frontend.

The motivation behind this feature is to reduce app startup time.

Maybe something like the following:

Configuration.Localization.Sources.Add(
    new DictionaryBasedLocalizationSource(
        "SimpleTaskSystem",
        new XmlFileLocalizationDictionaryProvider(
            HttpContext.Current.Server.MapPath("~/Localization/SimpleTaskSystem")
            )
        ),

                        clientVisibilityProvider: new VisibleSettingClientVisibilityProvider()
    );