[Challenge] Build a real Copy / Paste functionallity

[brauliodiez]

Right now copy / paste functionallity is just capturing the keyboard shortcuts and holding a local selection of the JSON of the shapes to be copied.

We should go one step forward an integrate the copy/paste with the Operating System one:

• User can copy from a different quick mock page.
• User can copy a given image from their favourite desktop image editing application.
• User can copy a text.

Then when pasting, it will check the copy/paste operating system queue and check if it's a compatible value (we will have to create some specific format for quick mock) and then paste it (depending on the input, as shapes, image, text...)