#4303: add search function.

Oqtane.Shared/Interfaces/ISearchService.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Oqtane.Models;
+
+namespace Oqtane.Services
+{
+    public interface ISearchService
+    {
+        void IndexContent(int siteId, DateTime? startTime, Action<string> logNote, Action<string> handleError);
+
+        Task<SearchResults> SearchAsync(SearchQuery searchQuery);
+    }
+}