examples/qemu: disable hardened preset

- Hardening is irrelevant in examples
- The decreased performance is especially noticeable in VMs

examples/qemu-vm/vm-config.nix

@@ -1,7 +1,12 @@
 {
+  # Disable the hardened preset to improve VM performance
+  disabledModules = [ <nix-bitcoin/modules/presets/hardened.nix> ];
+
+  config = {
     virtualisation.graphics = false;
     services.mingetty.autologinUser = "root";
     users.users.root = {
       openssh.authorizedKeys.keyFiles = [ ./id-vm.pub ];
     };
+  };
 }