added virtualbox, reformatted the homePacakges section to include pkgs by default in home.nix

added nix.settings.trusted-users so that I can add trusted substituters imperatively

home-manager/home.nix

@@ -48,13 +48,14 @@
         "Fuchsia-Pop";
 
   # General use home packages that dont require a separate module
-  home.packages = [
+  home.packages = with pkgs; [
     # Add grimblast screenshot tool
-    pkgs.grimblast
-    pkgs.powerline-fonts
-    pkgs.nix-output-monitor
-    pkgs.bitwarden-desktop
-    pkgs.xwaylandvideobridge
+    grimblast
+    powerline-fonts
+    nix-output-monitor
+    bitwarden-desktop
+    xwaylandvideobridge
+    virtualbox
   ];
 
   home.sessionVariables = {