Display and update App Name in settings (#3027)

* Edit and view app name in app settings

Currently the "name" property is not exposed at all in an app's settings/update page, which can result in confusion about which app is being updated, and also a general confusion between the `Title` property and the `Name` property.
This PR gives visibility to the app name in settings, and allows updating of the same.
I also changed the display label for `title` and `name` to make them more distinct and specific.

* Fix tests

* Update AltcoinTests.cs

* Update SeleniumTests.cs

* fix tests

Co-authored-by: Nicolas Dorier <nicolas.dorier@gmail.com>

BTCPayServer/Models/AppViewModels/UpdateCrowdfundViewModel.cs

@@ -10,9 +10,16 @@ namespace BTCPayServer.Models.AppViewModels
     {
         public string StoreId { get; set; }
         public string StoreName { get; set; }
+        
+        [Required]
+        [MaxLength(50)]
+        [MinLength(1)]
+        [Display(Name = "App Name")]
+        public string AppName { get; set; }
 
         [Required]
         [MaxLength(30)]
+        [Display(Name = "Display Title")]
         public string Title { get; set; }
 
         public string Tagline { get; set; }