massive rewrite using flake-parts

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

pkgs/default.nix

@@ -0,0 +1,14 @@
+{ self, ... }: {
+  systems = [ "x86_64-linux" ];
+
+  flake = {
+    overlays = rec {
+      packages = import ./packages.nix;
+      default = packages;
+    };
+  };
+
+  perSystem = { pkgs, ... }: {
+    packages = self.overlays.default null pkgs;
+  };
+}