Replaces SSH-based installation with serial console automation using a new send_line_to_vm function. The script now logs in, installs Podman, downloads and installs UniFi OS Server, and retrieves the VM IP address directly via the console. This simplifies the process and removes SSH and sshpass dependencies.
Replaces manual first-boot installer injection with a Cloud-Init user-data configuration for fully automated UniFi OS Server setup. Cloud-Init is now always enabled and required, simplifying image preparation and installation monitoring. Updates messaging and installation flow to reflect Cloud-Init usage and removes legacy non-Cloud-Init support.
Update the logic for detecting errors during base package pre-installation in unifi-os-server-vm.sh by checking for 'error' in the output. Also correct URLs in cloud-init.func to use the correct repository path.
