feat(packages): add fennel and fennel-ls

Built using `dream2nix`, based on my (reo101) forks of both projects

pkgs/fennel-ls/default.nix

@@ -0,0 +1,55 @@
+{ config
+, lib
+, dream2nix
+, ...
+}: {
+  imports = [
+    dream2nix.modules.dream2nix.mkDerivation
+  ];
+
+  deps = { nixpkgs, ... }: {
+    # Fetchers
+    inherit (nixpkgs)
+      fetchFromGitHub
+      ;
+
+    # Build inputs
+    lua = nixpkgs.luajit;
+    fennel = config.deps.lua.pkgs.fennel;
+  };
+
+  name = "fennel-ls";
+  version = "0.1.2-dev";
+
+  mkDerivation = {
+    src = config.deps.fetchFromGitHub {
+      owner = "reo101";
+      repo = config.name;
+      rev = "3099ba016b346696b8600dfbdffd9a66704f83f9";
+      hash = "sha256-H5znjiYuQEbNG2WyTvH1CbnSk5PzaoPNg+xc+y66Gq0=";
+    };
+
+    makeFlags = [
+      "PREFIX=$(out)"
+      "LUA=${lib.getExe' config.deps.lua "lua"}"
+      "FENNEL=${lib.getExe' config.deps.fennel "fennel"}"
+      "EXE=${config.mkDerivation.meta.mainProgram}"
+    ];
+
+    nativeBuildInputs = with config.deps; [
+    ];
+
+    buildInputs = with config.deps; [
+      # NOTE: `lua` and `fennel` provisioned using their corresponding `makeFlags`
+    ];
+
+    meta = with lib; {
+      description = "A language server for intelligent editing of the Fennel Programming Language";
+      homepage = "https://github.com/reo101/fennel-ls";
+      license = licenses.mit;
+      maintainers = with maintainers; [ reo101 ];
+      inherit (config.deps.lua.meta) platforms;
+      mainProgram = "fennel-ls";
+    };
+  };
+}