docs: remove Packer references and document cloud-init architecture decision

- Update project description to use OpenTofu/Terraform and cloud-init instead of Packer
- Add Architecture Decision section explaining why cloud-init was chosen over golden images
- Update all documentation files for consistency
- Emphasize cross-cloud compatibility and simplicity as key decision factors

Author: josecelano

.github/copilot-instructions.md

@@ -1,6 +1,6 @@
 # Torrust Tracker Deployment Tool
 
-A modern Perl console application for deploying Torrust Tracker to Hetzner Cloud using Packer, Terraform, and Ansible.
+A modern Perl console application for deploying Torrust Tracker to cloud providers using OpenTofu/Terraform and cloud-init for VM configuration.
 
 ## Code Quality Standards
 

README.md

@@ -2,8 +2,22 @@
 
 # Torrust Tracker Deployment Tool
 
-A modern Perl console application for deploying Torrust Tracker to Hetzner Cloud using Packer,
-Terraform, and Ansible.
+A modern Perl console application for deploying Torrust Tracker to cloud providers using
+OpenTofu/Terraform and cloud-init for VM configuration.
+
+## Architecture Decision: Cloud-Init vs Golden Images
+
+This project uses cloud-init for VM configuration instead of building golden images with tools like
+Packer. While golden images could speed up provisioning by pre-installing the torrust user, Docker,
+and other basic setup, we chose cloud-init because:
+
+- **Cross-cloud compatibility**: No way to generate a single base image that works across multiple  
+  cloud providers
+- **Deployment frequency**: Since deployment is typically done once, the extra time for cloud-init  
+  configuration is acceptable
+- **Simplicity**: Eliminates the complexity of managing and maintaining custom images across  
+  different providers
+- **Transparency**: All VM configuration is visible in the cloud-init templates
 
 ## Perl Version Requirement
 

lib/TorrustDeploy/App.pm

@@ -4,7 +4,7 @@ use v5.38;
 
 # App::Cmd framework setup - automatically discovers commands in TorrustDeploy::App::Command::*
 # Commands are found by convention: each .pm file in lib/TorrustDeploy/App/Command/ 
-# becomes a command (e.g., help.pm -> "help" command, packer.pm -> "packer" command)
+# becomes a command (e.g., provision.pm -> "provision" command)
 use App::Cmd::Setup -app;
 
 sub usage_desc { "%c %o" }
@@ -26,8 +26,8 @@ TorrustDeploy::App - Deploy Torrust Tracker to Hetzner Cloud
 
 =head1 DESCRIPTION
 
-A modern Perl console application for deploying Torrust Tracker to Hetzner Cloud
-using Packer, Terraform, and Ansible.
+A modern Perl console application for deploying Torrust Tracker to cloud providers
+using OpenTofu/Terraform and cloud-init for VM configuration.
 
 =head1 AUTHOR