system/greetd,users/rin: split into xorg and wayland

modules/system/greetd_xorg.nix

@@ -0,0 +1,16 @@
+{ pkgs, lib, ... }: {
+  services.greetd = {
+    enable = true;
+    settings = {
+      default_session = {
+        command = "${pkgs.greetd.tuigreet}/bin/tuigreet --remember --asterisks --time --cmd 'zsh -c \"source $HOME/.config/zsh/.zshrc && startx\"'";
+        user = "greeter";
+      };
+    };
+  };
+
+  services.xserver = {
+    autorun = false;
+    displayManager.startx.enable = true;
+  };
+}