Add scan option to force gallery zip rescan (#4113)

* Add scan option to force rescan
---------
Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

pkg/file/scan.go

@@ -134,6 +134,9 @@ type ScanOptions struct {
 	HandlerRequiredFilters []Filter
 
 	ParallelTasks int
+
+	// When true files in path will be rescanned even if they haven't changed
+	Rescan bool
 }
 
 // Scan starts the scanning process.
@@ -1023,14 +1026,20 @@ func (s *scanJob) onExistingFile(ctx context.Context, f scanFile, existing model
 
 	fileModTime := f.ModTime
 	updated := !fileModTime.Equal(base.ModTime)
+	forceRescan := s.options.Rescan
 
-	if !updated {
+	if !updated && !forceRescan {
 		return s.onUnchangedFile(ctx, f, existing)
 	}
 
 	oldBase := *base
 
-	logger.Infof("%s has been updated: rescanning", path)
+	if !updated && forceRescan {
+		logger.Infof("rescanning %s", path)
+	} else {
+		logger.Infof("%s has been updated: rescanning", path)
+	}
+
 	base.ModTime = fileModTime
 	base.Size = f.Size
 	base.UpdatedAt = time.Now()