[NixOS] Add python to essential

nixos/essential.nix

@@ -1,6 +1,23 @@
 { pkgs, ... }:
+let
+  my-python-packages = python-packages: with python-packages; [
+    appdirs
+    ipdb
+    ipython
+    numpy
+    openpyxl
+    pip
+    requests
+    tox
+    virtualenv
+    virtualenvwrapper
+  ];
+  python-with-my-packages = pkgs.python3.withPackages my-python-packages;
+in
 {
   environment.systemPackages = with pkgs; [
+    python-with-my-packages
+
     emacs
     firefox
     vlc
@@ -53,7 +70,7 @@
 
     # Tools
     binutils
-    direnv
+    # direnv
     gitFull
     rcm
     ripgrep