Add U2f Login Support (#787)

* init u2f

* ux fixes

* Cleanup Manage Controller

* final changes

* remove logs

* remove console log

* fix text for u2f

* Use Is Secure instead of IsHttps

* add some basic u2f tests

* move loaders to before title

* missing commit

* refactor after nicolas wtf moment

BTCPayServer/U2F/Models/LoginWithU2FViewModel.cs

@@ -0,0 +1,28 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace BTCPayServer.Services.U2F.Models
+{
+    public class LoginWithU2FViewModel
+    {
+        public string UserId { get; set; }
+        [Required]
+        [Display(Name = "App id")]
+        public string AppId { get; set; }
+
+        [Required]
+        [Display(Name = "Version")]
+        public string Version { get; set; }
+
+        [Required]
+        [Display(Name = "Device Response")]
+        public string DeviceResponse { get; set; }
+
+        [Display(Name = "Challenges")]
+        public string Challenges { get; set; }
+
+        [Display(Name = "Challenge")]
+        public string Challenge { get; set; }
+
+        public bool RememberMe { get; set; }
+    }
+}