Refactor the whole configuration

Reviewed-on: #1

modules/nixos/communication/default.nix

@@ -0,0 +1,22 @@
+{ pkgs, username, ... }:
+
+{
+  environment.systemPackages = with pkgs; [
+    tutanota-desktop
+    signal-desktop
+    element-desktop
+    vesktop
+  ];
+
+  environment.persistence."/nix/persist" = {
+    users."${username}" = {
+      directories = [
+        ".config/Signal"
+        ".config/vesktop"
+        ".config/tutanota-desktop"
+        ".config/tuta_integration"
+        ".config/Element"
+      ];
+    };
+  };
+}