Fustellare generally means to punch a hole in something, usually thin light things like paper and card. `Die-cut` (given in Marolli) sounds worryingly technical, but it simply refers to the fact that the punch can also be called a die, though `die` suggests that it is a very accurately made one, which I don't think is implied by `fustellare` because `fustellare` is so common in texts about the cutting out of cardboard blanks for containers. I personally would put `punched`.
I picture this contenitore in cartone (cardboard container) as having holes punched in its top surface (or possibly in a second sheet placed inside it). Bottles or the like can then be placed in these holes and the holes will stop the bottles falling over or rubbing against against each other. The fact that the writer says `alveoli` suggests that the holes have depth, so I imagine the holes are formed by cutting a sort of star pattern and then folding the arms of the star down. This would give a cm or so of support down the vertical sides of the bottles, and would explain the choice of the word `alveoli`.