Improve hls situation

This is the default build due it being necessary for working with template haskell and quasi quotes, but some changes need to be made for the dynamic executable to work on nix.

Downgraded fourmolu as latest version only works with ghc-lib-parser 9.8+, but hlint doesn't support this yet. Added cabal-fmt which was missing (I'm unsure if it's not working in my setup because of my config, or because the plugin needs more help locating the executable)