feature : additional changes to the workspace directory deletion

[achalbajpai]

I was currently reviewing the codebase and noticed that the clean-up-workspaces.py only checks the timestamp of directories and immediately deletes the files that are older than 7 days.

How about we have something , that allows to

• Check the file timestamp ( the directory timestamp might not detect the file changes we might do while working )
• Give a warning before deletion ( a log file file can be great as we dont have any smtp )
• Creating a backup workspace files ( either user can have access locally / conterize it )