Add support for copy more than 1 card to the clipboard

[einfall]

Hello,
When I create different dashboards and copy a card to the next dashboard view, it would be great if it were possible to copy multiple cards to the clipboard at once.

[marcinbauer85]

Most, if not all, clipboard solutions can have just one active element at a time. We can consider copying a whole section to the clipboard and having that as an alternative solution for this issue.

[wendevlin]

Hey @einfall, do you have an idea (einfall 😆) how this UI would look like?
I just can't think of a good way to don't overload the UI.

Moreover you could just use yaml to copy a bunch of cards.