feat(configuration): add thumbnail snap range setting

src/Eve-O-Preview/Configuration/Interface/IThumbnailConfiguration.cs

@@ -53,6 +53,7 @@ namespace EveOPreview.Configuration {
         Size ThumbnailMaximumSize { get; set; }
 
         bool EnableThumbnailSnap { get; set; }
+        int ThumbnailSnapRange { get; set; }
 
         bool ThumbnailZoomEnabled { get; set; }
         int ThumbnailZoomFactor { get; set; }