Add a copy action on notification

[ValekoZ]

When I try to send something from my phone to my computer, I can easily accept the transfer from the notification (using the do_action of dunst)
But then, I need to open rquickshare interface to copy the text or open the image for copying it.
It would be awesome to have an action directly from the notification to copy the text/image, so that we wouldn't have to open the GUI at all :p