Add many PrivateApi attributes to hide unimportant stuff in docs

Oqtane.Server/Infrastructure/SiteTemplates/DefaultSiteTemplate.cs

@@ -6,9 +6,11 @@ using Microsoft.AspNetCore.Hosting;
 using Oqtane.Extensions;
 using Oqtane.Shared;
 using System.IO;
+using Oqtane.Documentation;
 
 namespace Oqtane.SiteTemplates
 {
+    [PrivateApi("Mark Site-Template classes as private, since it's not very useful in the public docs")]
     public class DefaultSiteTemplate : ISiteTemplate
     {