uBlock Origin already has this. Enable the "Cookie notices" and "Annoyances" filters in uBlock Origin's settings.
Bonus pro-tip: Firefox for Android supports uBlock Origin, which means you can get rid of these godawful banners on mobile, too. Only iOS users are stuck having to put up with them.
Bonus pro-tip: Firefox for Android supports uBlock Origin, which means you can get rid of these godawful banners on mobile, too. Only iOS users are stuck having to put up with them.