feat!(flake): update homix

Add more & generalize flake outputs:
    - templates: just a `default.nix` (TODO: add a `Haskell` template)
    - packages & devShells: create and use `forEachPkgs`
Add more `Wayland` things for `homix`:
    - `swww` - custom package + custom systemd service (TODO: abstract away)
    - `wired` - from flake + `home-manager` module
Add default `imports` and `nixokgs.overlays` for `reo101@homix`
    -- TODO: don't handwire it, somehow *auto-import* from `mkNixosHost` in `flake.nix`

machines/nixos/x86_64-linux/__template__/hardware-configuration.nix

@@ -0,0 +1,10 @@
+# This is just an example, you should generate yours with nixos-generate-config and put it in here.
+{
+  fileSystems."/" = {
+    device = "/dev/sda1";
+    fsType = "ext4";
+  };
+
+  # Set your system kind (needed for flakes)
+  nixpkgs.hostPlatform = "x86_64-linux";
+}