#4303: add search function.

Oqtane.Shared/Interfaces/ISearchIndexManager.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Web;
+using Oqtane.Models;
+
+namespace Oqtane.Services
+{
+    public interface ISearchIndexManager
+    {
+        int Priority { get; }
+
+        string Name { get; }
+
+        bool IsIndexEnabled(int siteId);
+
+        int IndexDocuments(int siteId, DateTime? startTime, Action<IList<SearchDocument>> processSearchDocuments, Action<string> handleError);
+    }
+}