Add OCaml Koans

[pmetzger]

See:
https://web.archive.org/web/20031105005932/www.bagley.org/~doug/ocaml/Notes/okoans.shtml

Pointed out to me by @Drup.

[mars0i]

I was thinking the same thing. A link on the Learning page? (Not sure it's actually educational, but it's fun.)

[pmetzger]

It's only in the internet archive. We should probably rescue the actual text onto OCamlverse.

[bluddy]

Go for it.

Only place I can think of linking it from right now is the learning page.