refactor: split common/nixos.nix and -/home.nix

Split these big files into modular files that
are easier to share and read on their own.

profiles/common/nixos/env.nix

@@ -0,0 +1,16 @@
+{ lib, pkgs, ... }:
+{
+  environment = {
+    wordlist.enable = true;
+    sessionVariables = {
+      NIXOS_OZONE_WL = "1";
+      GST_PLUGIN_SYSTEM_PATH_1_0 = lib.makeSearchPathOutput "lib" "lib/gstreamer-1.0" (with pkgs.gst_all_1; [
+        gst-plugins-good
+        gst-plugins-bad
+        gst-plugins-ugly
+        gst-libav
+      ]);
+    };
+  };
+  # gstreamer plugins for nautilus (used for file metadata)
+}