Add page with designs for stickers and other merch items

[wetneb]

OpenRefine merchandise is often popular in in-person events. We could have a page with designs that people can reuse and print locally.

I have printed the following as a sticker, based on the design by Scott Carlson (CC-BY-SA)
https://pintoch.ulminfo.fr/e4e64a3555/Open_Refine_is_Magic.png
(my version adds a bit more margin so that it's easier to cut around the border)

@Ainali mentioned that he could share the design for a very nice jersey

We could surely find more options.

[Ainali]

These are the files I used for my t-shirt.
Front:

Left arm:

Right arm:

Back:

And here is me wearing it, unfortunately the arms do not show well. I ordered the Athletic t-shirt from Printful which is a nice sporty t-shirt (and hence the sweat, sorry for that).