add support for named site options

Oqtane.Server/Infrastructure/Options/ISiteNamedOptions.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+using Oqtane.Models;
+
+namespace Oqtane.Infrastructure
+{
+    public interface ISiteNamedOptions<TOptions>
+        where TOptions : class, new()
+    {
+        void Configure(string name, TOptions options, Alias alias, Dictionary<string, string> sitesettings);
+    }
+}