stack.yaml: Use -Werror on all packages
stack.yaml: Use -Werror on all packages

Also remove disabling of Haddock due to swagger2 and ghc 8.0.

input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl