Added support for per site options and OpenID Connect

Oqtane.Server/Infrastructure/Options/ISiteOptions.cs

@@ -0,0 +1,12 @@
+
+using Oqtane.Models;
+
+namespace Oqtane.Infrastructure
+{
+    public interface ISiteOptions<TOptions, TAlias>
+        where TOptions : class, new()
+        where TAlias : class, IAlias, new()
+    {
+        void Configure(TOptions options, TAlias siteOptions);
+    }
+}