For ports with USES=cabal install a wrapper shell script instead of a real executable into /bin/, that sets some environment variables to workaround https://github.com/haskell/cabal/issues/5997
While there, update bunch of Haskell ports, make them install their data files.
Unbreak math/hs-Agda.
PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=237878