Removes IdentityServer4 usage

Views/Shared/_Nav.cshtml

@@ -1,10 +1,9 @@
-@using IdentityServer4.Extensions
-
+
 @{
     string name = null;
     if (!true.Equals(ViewData["signed-out"]))
     {
-        name = Context.User?.GetDisplayName();
+        name = User.Identity.Name;
     }
 }
 
@@ -13,7 +12,7 @@
 
         <a href="~/" class="navbar-brand">
             <img src="~/icon.png" class="icon-banner">
-            IdentityServer4
+            Nuget host
         </a>
 
         @if (!string.IsNullOrWhiteSpace(name))