WIP: Remove mails when all copying is done

Could be improved in 'when _each_ copy is done' I suppose.

There aren't any undo popups anymore. But it works.
3 jobs for 645-foreign-copy in 16 minutes and 53 seconds (queued for 1 second)
Status Job ID Name Coverage
  .Pre
passed #520128
flatpak

00:11:43

 
  Build
passed #520129
fedora

00:05:10

passed #520130
ubuntu

00:04:47