Ability to delete media and associated files

New feature with the ability to let SickRage delete media files automatically when the status of an episode is changed to the desired state (directly or with a delay time in minutes to prevent mistakes)

This feature is not done yet, but I'm stuck. The following needs more work: 
- use data from table delete_media and if the delay time is passed delete the files
- ability to cancel deletion of files on displayshow page before delay time is passed

More info: https://sickrage.tv/forums/forum/main-category/feature-requests/10193-ability-to-delete-media-and-associated-files