GHC 9.6+ updates

[dmjio]

Hey @csabahruska,

In preparation for @mpickering and @alt-romes to release an alpha version of dap integration w/ GHC, I'd like to ensure that our work with the haskell-estgi-debugger is building along with the coming dap changes.

This PR updates the external-stg-interpreter, external-stg and external-stg-syntax to build with GHC 9.6+.

Things done:

• Adjusted primops and tests for 64-bit Word and Int since ghc-prim had slightly changed (primop tests pass now ✅ )
• cabal.project file was added and it does build with the latest souffle-haskell-0.4.0.0 and a working version of final-pretty
• A cabal flag was introduced (-fexternal-ext-stg-gc and -fexternal-ext-liveness-analysis -- disabled by default in the cabal file - but enabled by default in cabal.project) to allow users to build the souffle generated C++ by hand. This simplifies the build, and runSouffle is able to find the ext-stg-gc binary in $PATH.
• Re-introduced import Control.Monad, it was decided that Control.Monad should no longer be re-exported from mtl modules.
• Adds a github workflow file. This workflow will use cabal's resolver to build the Haskell code, and nix to acquire bzip2 and zlib.
• Adds a github workflow badge to the README.md

    neWord16# [✔]
     +++ OK, passed 100 tests.

Finished in 0.0904 seconds
240 examples, 0 failures
Test suite primop-test: PASS
Test suite logged to:
/home/dmjio/Desktop/ghc-whole-program-compiler-project/dist-newstyle/build/x86_64-linux/ghc-9.6.6/external-stg-interpreter-0.1.0.1/t/primop-test/test/external-stg-interpreter-0.1.0.1-primop-test.log
1 of 1 test suites (1 of 1 test cases) passed.

^ these tests should run in CI now

Then in the haskell-debugger I'm able to make ext-stg-gc available on PATH so runSouffle will always be able to find it, when we call the external-stg-interpreter from haskell-debugger.

  ext-stg-gc =
    pkgs.stdenv.mkDerivation {
      name = "ext-stg-gc";
      src = "${ghc-wpo-src}/external-stg-interpreter";
      buildInputs = with pkgs; [ souffle openmpi ];
      buildPhase = ''
        mkdir -pv $out/bin
        g++ -fopenmp $src/datalog/ext-stg-gc.cpp \
           -D_OPENMP -std=c++17 \
           -o $out/bin/ext-stg-gc
      '';
    };
    ```

[dmjio]

Since we've updated souffle, we've regen'd the reachability analysis for GC (per the README.md instructions).

It seems to build and do the right thing (checks roots for mark and sweep)

❯ $(nix-build -A ext-stg-gc)/bin/ext-stg-gc
Error loading GCRoot data: Cannot open fact file GCRoot.facts