Simplified emacs setup and made it default

hosts/nixos/default.nix

@@ -334,6 +334,20 @@ in
   ];
 
   environment.systemPackages = with pkgs; [
+    # Emacs with automatic package management from overlay
+    (emacsWithPackagesFromUsePackage {
+      config = ../config/emacs/emacs.el;
+      defaultInitFile = true;
+      package = emacs-unstable;
+      alwaysEnsure = true;
+      extraEmacsPackages =
+        epkgs: with epkgs; [
+          magit
+          company
+          nix-mode
+          use-package
+        ];
+    })
     gitAndTools.gitFull
     inetutils
   ];