Services, refactor, clean up, service to automatic

Move service to automatic since it has a separate purpose.

Refactor the default.nix code to include service.nix files so it is
easier to extend code.

nixosModules/services/pipewire/service.nix

@@ -0,0 +1,21 @@
+{ config, pkgs, lib, ... }:
+
+{
+  options.pipewire = {
+    enable = lib.mkEnableOption "Enables pipewire and pulsemixer";
+  };
+
+  config = lib.mkIf config.pipewire.enable {
+    security.rtkit.enable = true;
+    services.pipewire = {
+      enable = true;
+      wireplumber.enable = true;
+      alsa.enable = false;
+      alsa.support32Bit = false;
+      pulse.enable = true;
+    };
+    environment.systemPackages = with pkgs; [
+      pulsemixer
+    ];
+  };
+}