Delete files left in the temp folder without affecting the ongoing converting

[xiaofengxie128]

When files are first uploaded to "/var/temp" (inside containers), they will normally be deleted or moved after extraction or other processing. However, if somehow the processing failed or system shut down (all rare cases), files can accumulate in this folder and need be purged without affect ongoing process.

Proposed solutions:
Record file list inside /var/temp in the daily process (inside automated_tasks.py) to a file, and purge all the files and folders in that list next day.