profiles/serial-console: Add profile for serial console and enable on mercury VMs be default

profiles/serial-console/default.nix

@@ -0,0 +1,26 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+
+  cfg = config.profiles.clerie.serial-console;
+
+in {
+
+  options.profiles.clerie.serial-console = {
+    enable = mkEnableOption "Use first serial console as termial";
+  };
+
+  config = mkIf cfg.enable {
+
+    boot.kernelParams = [ "console=ttyS0,115200n8" ];
+
+    boot.loader.grub.extraConfig = "
+      serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1
+      terminal_input serial
+      terminal_output serial
+    ";
+
+  };
+}