Added support for per site options and OpenID Connect

Oqtane.Server/Extensions/HttpContextExtensions.cs

@@ -0,0 +1,18 @@
+using Microsoft.AspNetCore.Http;
+using Oqtane.Models;
+using Oqtane.Shared;
+
+namespace Oqtane.Extensions
+{
+    public static class HttpContextExtensions
+    {
+        public static Alias GetAlias(this HttpContext context)
+        {
+            if (context != null && context.Items.ContainsKey(Constants.HttpContextAliasKey))
+            {
+                return context.Items[Constants.HttpContextAliasKey] as Alias;
+            }
+            return null;
+        }
+    }
+}