Regarding Implementing localization in ASP.NET Core

see the code i have read this article https://dotnetthoughts.net/implementing-localization-in-aspnet-core/ but do not understand many things.

public void Configure(IApplicationBuilder app)
{
    var supportedCultures = new List<CultureInfo>
    {
        new CultureInfo("en-US"),
        new CultureInfo("ml-IN"),
        new CultureInfo("hi-IN")
    };

    var options = new RequestLocalizationOptions
    {
        DefaultRequestCulture = new RequestCulture("en-US"),
        SupportedCultures = supportedCultures,
        SupportedUICultures = supportedCultures,
    };

    app.UseRequestLocalization(options);
    app.UseStaticFiles();

    app.UseMvcWithDefaultRoute();
}

1) in asp.net mvc 4 or 5 we used to assign culture to thread and threadUI....but see the above code they are not assigning any culture to thread and threadUI.

2) see the code

public class HomeController : Controller
{
    private readonly IStringLocalizer<HomeController> _stringLocalizer;
    public HomeController(IStringLocalizer<HomeController> stringLocalizer)
    {
        _stringLocalizer = stringLocalizer;
    }
    public IActionResult Index()
    {
        ViewData["Welcome"] = _stringLocalizer["Welcome"];
        return View();
    }
}

2) what is IStringLocalizer and we never use thisIStringLocalizer in old mvc4/5. whatIStringLocalizer does ?

3) in asp.net webform or asp.net mvc we can give any name to resource file but the above article link is saying we need to give resource file nameHomeController.en-US.resx and HomeController.en-UK.resx. if i give any name like myresource-.en-US.resx then it will not work ?

4) what is the meaning of app.UseStaticFiles(); ? when we need to say this app.UseStaticFiles(); only for resource file ?

5) what is the meaning of services.AddLocalization(options => options.ResourcesPath = "Resources"); ?resource is the name of the folder?

6) why we need to say services.AddMvc(); when we are working with asp.net mvc core then we need to mention add mvc?

please guide me and answer point wise. thanks