[emacs] Modularize more and better pkg

Attempts to select the right emacs package based on whether the machine
is x11 only or not.

home/home-default.nix

@@ -1,8 +1,5 @@
-{ pkgs, ... }:
+{ pkgs, customPkgs, ... }:
 
-let
-  nextcloudTalkDesktop = pkgs.callPackage ./modules/nextcloud-talk-desktop/package.nix {};
-in
 {
   # Home Manager needs a bit of information about you and the paths it should
   # manage.
@@ -62,7 +59,7 @@ in
     pkgs.wofi
     pkgs.vlc
 
-    nextcloudTalkDesktop
+    customPkgs.nextcloudTalkDesktop
   ];
 
   # Home Manager is pretty good at managing dotfiles. The primary way to manage