fix: [#28] resolve e2e testing blockers for local development

- Fix markdown linting error in grafana-subdomain-setup.md (MD029/ol-prefix)
  * Change ordered list numbering from '2.' to '1.' for proper sequence
- Fix libvirt cloud-init template variable passing in main.tf
  * Add missing 'use_minimal = var.use_minimal_config' parameter
  * Ensures cloud-init templates receive all required variables

These fixes enable successful e2e testing in local development environments
and ensure consistent template rendering across different deployment modes.

Author: josecelano

docs/guides/grafana-subdomain-setup.md

@@ -119,7 +119,7 @@ cd /home/torrust/github/torrust/torrust-tracker-demo/application
 docker compose --env-file /var/lib/torrust/compose/.env exec proxy nginx -s reload
 ```
 
-2. **Test the subdomain:**
+1. **Test the subdomain:**
 
 ```bash
 # From your local machine

infrastructure/terraform/providers/libvirt/main.tf

@@ -56,6 +56,7 @@ resource "libvirt_cloudinit_disk" "commoninit" {
   name           = "${var.vm_name}-cloudinit.iso"
   user_data      = templatefile("${path.module}/../../../cloud-init/${var.use_minimal_config ? "user-data-minimal.yaml.tpl" : "user-data.yaml.tpl"}", {
     ssh_public_key = var.ssh_public_key
+    use_minimal    = var.use_minimal_config
   })
   meta_data      = templatefile("${path.module}/../../../cloud-init/meta-data.yaml", {
     hostname = var.vm_name