Refactor: Docker-VM (Multi-OS / Cloud-Init / Stabilization)

[MickLesk]

✍️ Description

• Multi-OS Support – Added Debian 12/13 + Ubuntu 22.04/24.04 selection via select_os()
• Cloud-Init Integration – Optional Cloud-Init config; Ubuntu auto-enabled, Debian optional
• Modular Architecture – External function files (vm-core.func, cloud-init.func, api.func) from git.community-scripts.org
• Better Defaults – Q35 instead of i440fx; Host CPU instead of KVM64; 4GB RAM instead of 2GB
• Docker via get.docker.com – Replaced manual repo setup with official one-liner + first-boot fallback service
• Image Caching – Downloads cached in /var/lib/vz/template/cache/ for reuse
• Simplified Disk Resize – Uses qemu-img resize instead of virt-resize
• Auto-Login for nocloud – Serial console auto-login configured when Cloud-Init disabled
• IP Detection – Automatic IP retrieval via QEMU guest agent in final summary
• Code Cleanup – Removed inline ASCII art/colors; added section separators; fixed function naming (exit_script)

🔗 Related PR / Issue

Fixes: #9040

✅ Prerequisites (X in brackets)

• Self-review completed – Code follows project standards.
• Tested thoroughly – Changes work as expected.
• No security risks – No hardcoded secrets, unnecessary privilege escalations, or permission issues.

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🛠️ Type of Change (X in brackets)

• 🐞 Bug fix – Resolves an issue without breaking functionality.
• ✨ New feature – Adds new, non-breaking functionality.
• 💥 Breaking change – Alters existing functionality in a way that may require updates.
• 🆕 New script – A fully functional and tested script or script set.
• 🌍 Website update – Changes to website-related JSON files or metadata.
• 🔧 Refactoring / Code Cleanup – Improves readability or maintainability without changing functionality.
• 📝 Documentation update – Changes to README, AppName.md, CONTRIBUTING.md, or other docs.

[Yash-xoxo]

switch to arch?

[MickLesk]

No

[Yash-xoxo]

suffer

[AnthonyMichaelTDM]

I see that this is a draft until tested, I didn't test the script directly, but I did migrate my docker vm (created a long time ago with the script currently in main) from Debian 12 to Debian 13 and haven't had issues.

[dafi87]

I would test this but I'm on PVE 9.1.2, which isn't supported by your updated script yet.

[MickLesk]

Sure in Dev repo

[dafi87]

I thought the point was to test what's in this pull request. But thanks anyway.