cabal: don't use internal libraries
Cabal Internal Libraries are a feature currently used to split cql-io into cql-io{,-lib}. This is nice, but is currently not very well supported by tooling. Witness the trail of destruction:
- Haddock doesn't like them: https://github.com/haskell/cabal/issues/4969
- Stack doesn't like them: https://github.com/commercialhaskell/stack/pull/4596
- And now Bazel haskell_rules doesn't seem to support them (filing a bug for this later)
I don't generally like bypassing broken tooling by rolling down on features, but I'd also like to avoid having to use a fork of cql-io with just the internal libraries neutered (as we still see issues with Haddock and Stack on our side). As such, this is more a Merge Pretty Please than a Merge Request :).