moved home manager user configuration to dedicated files

aspects/users/user_io.nix

@@ -0,0 +1,32 @@
+{ inputs, lib, ... }:
+
+{
+  flake."user@io" = inputs.home-manager.lib.homeManagerConfiguration {
+    pkgs = inputs.nixpkgs.legacyPackages.x86_64-linux;
+    extraSpecialArgs = {
+      inherit inputs;
+      hostname = "io";
+    };
+    modules = [
+      { nixpkgs.overlays = [ inputs.self.overlays.default ]; }
+      {
+        home = {
+          username = "user";
+          homeDirectory = "/home/user";
+          stateVersion = "22.05";
+        };
+      }
+      ((inputs.import-tree.initFilter (p: lib.hasSuffix ".nix" p)) ./_user)
+    ]
+    ++ (with inputs.self.modules.homeManager; [
+      # system aspects
+      base
+      cli
+      desktop
+
+      # other aspect
+      stylix
+      niri
+    ]);
+  };
+}