This will eventually allow the notification applet to show a better finished notification.
Currently, it just uses whatever was set as second info label last. While this works for when copying a single file, it's utterly wrong when copying folders as this will be a random file that was copied last.

I can now (still wip local patches I need to clean up a bit)

• show the destination of a job while it's still figuring out what do copy (e.g. when no info label 2 is set, I'll show dest Url there instead)
• show Copying finished: /foo/bar instead of Copying finished: /foo/bar/some/random/file/that/was/copied/also.txt (need to figure out so a single file copied/received still shows the full path for easy access)

Depends on D3818