Provide the base URL if possible for Sonarr/Radarr.

If the API returns a base URL that differs from the one currently set, output that in the error message.
Even though Sonarr/Radarr return a result here, they will fail for POST requests, so this does need to be set correctly.

src/Ombi.Core/Models/TesterResultModel.cs

@@ -0,0 +1,8 @@
+namespace Ombi.Core.Models
+{
+    public class TesterResultModel
+    {
+        public bool IsValid { get; set; }
+        public string ExpectedSubDir { get; set; }
+    }
+}