Deprecate Haskell bindings

I personally consider the thrift Haskell library not production ready due to e.g. THRIFT-5098 and THRIFT-5231. I would recommend that you instead suggest that people use one of the following two alternative implementations:

hsthrift:

https://github.com/facebookincubator/hsthrift

pinch/pinch-gen:

https://github.com/abhinav/pinch#readme

https://github.com/phile314/pinch-gen/