Add 'Make a Copy...' button to notebook Dashboard

The option 'Make a Copy...' from the file menu in the notebook is
available also in the notebooks Dashboard.

I am exposing the same functionality that the 'Make a Copy...' button does inside the notebook.
This is linked to #1877 and appears in the wishlist milestone.

Note: I need some help implementing tests for this, since I wanted to start from a test on a
similar feature but couldn't find it.