add file log page to cm

* Only send and receive logs are shown
* For older version, client send to server doesn't have size information, because server side doesn't know the total_size
* Not switch tabs automatically when new files are transferred
* If cm side page is open, not pop up automatically when new files are transferred
* Show unread message count
* The cm tab remains open when closed if a file transfer has previously occurred

Signed-off-by: 21pages <pages21@163.com>

flutter/lib/models/file_model.dart

@@ -1029,6 +1029,7 @@ class JobProgress {
   var to = "";
   var showHidden = false;
   var err = "";
+  int lastTransferredSize = 0;
 
   clear() {
     state = JobState.none;