Add the Shako Chess format!

@Toadofsky What do you really think about this variation?

The thing is, these require a lot of work to add. Lichess isn't some huge corporation with hundreds of devs working together, and it takes a long time. On top of that, they have to design the new pieces in the variant with all the piece styles; that would take weeks by itself. With something this complicated, just one person wanting it isn't going to make it be added. If it was a super cool variant, easy to code, or lots of people wanted it, then maybe there would be a chance. With a largely unheard of variant, barely any supporters, and a complicated variant at that, it most likely won't get added. You posting a link to this post in other unrelated posts isn't helping either.

@UtnapishtimBR there are countless variant candidates exist. See github.com/ornicar/lila/issues/441
But seems there is very little chance for them to be implemented on lichess:
lichess.org/forum/lichess-feedback/seirawan-chess?page=3#22

SAD! :(