add haskell docs

Attempt to add Haskell docs, which I noticed are not currently live on DockerHub ( https://registry.hub.docker.com/_/haskell/ ).  Let me know if I have anything wrong and I'll fix it up.

ping @darinmorrison @ChristopherBiscardi
Unless I'm counting wrong, this is 160 characters.  The Hub team decided that 100 is the new maximum, unfortunately. :frowning: