make downloads direct itch boxes

Embedding the itch boxes is easy:

<iframe src="https://itch.io/embed/2789419" width="552" height="167" frameborder="0"><a href="https://bindrpg.itch.io/rules">BIND Rules by Andonome</a></iframe>

...at least it works fine when testing in the 'About' page:

BIND (_**B**IND **I**s **N**ot **D**&D_) manifests the philosophy of FOSS (_**F**ree and **O**pen **S**ource **S**oftware_) in a grunge-fantasy TTRPG.

<iframe src="https://itch.io/embed/2789419" width="552" height="167" frameborder="0"><a href="https://bindrpg.itch.io/rules">BIND Rules by Andonome</a></iframe>

It does not work in the actual entries on the front page.

But maybe the buttons could just be replaced with itch links? They're defined in this file, using golang templates:

themes/hugoplate/layouts/partials/essentials/header.html

I don't speak 'go', but maybe there's a snappy way to do this?

...but then again, the itch.io links just redirect to the page (just like the butto), so it's functionally the same thing.

So if this turns out to be difficult, it's probably not worth the time.