restructure

- users/rin/default.nix -> users/rin.nix
- users/rin/home.nix +-> users/rin.nix
- users/rin/*.nix -> modules/user/*.nix
- users/rin/scripts/ -> scripts/
- hosts/winter/default.nix -> hosts/winter.nix
- hosts/winter/*.nix -> modules/system/*.nix

- modules are dynamically imported as sets for system and user

modules/system/gui.nix

@@ -0,0 +1,46 @@
+{ config, lib, pkgs, ... }: {
+  fonts = {
+    enableDefaultFonts = true;
+    fontconfig = {
+      defaultFonts = {
+        serif = ["NotoSerif"];
+        sansSerif = ["NotoSans"];
+        monospace = ["CascadiaCode"];
+      };
+    };
+    fonts = with pkgs; [
+      cascadia-code
+      font-awesome-ttf
+      font-awesome_4
+      hanazono
+      material-icons
+      noto-fonts
+      noto-fonts-cjk
+      noto-fonts-extra
+      open-sans
+      twemoji-color-font
+      unifont
+    ];
+  };
+  services.xserver = {
+    enable = true;
+    autorun = false;
+    displayManager = {
+      lightdm.enable = lib.mkForce false;
+      startx.enable = true;
+      xserverArgs = [
+        "-ardelay 250"
+        "-arinterval 15"
+      ];
+    };
+    desktopManager.xterm.enable = false;
+    libinput = {
+      enable = true;
+      mouse = {
+        accelSpeed = "0";
+        accelProfile = "flat";
+      };
+    };
+    xkbOptions = "caps:escape";
+  };
+}