ResourceNodes: Add copy to clipboard actions.

One for :/prefix/file paths and one as a url qrc:///prefix/file

Task-number: QTCREATORBUG-11776

Change-Id: I98cc2fccf98a6bf07487352e9b10ae29e8347a45
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>