Refactor: Stirling-PDF

[MickLesk]

✍️ Description

full refactor of stirling-pdf
now missing tools are available too (new unoserver service)

=> For all old users, its better to recreate the LXC

Edit, build an check for old installs with exit, so users need to recreate.
if [[ ! -f /etc/systemd/system/unoserver.service ]]; then
msg_custom "⚠️ " "\e[33m" "Legacy installation detected – please recreate the container using the latest install script."
exit 0
fi

🔗 Related PR / Issue

Link: #5816

✅ 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.

---

🛠️ 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.

[MickLesk]

Edit, build an check for old installs with exit, so users need to recreate.

if [[ ! -f /etc/systemd/system/unoserver.service ]]; then
msg_custom "⚠️ " "\e[33m" "Legacy installation detected – please recreate the container using the latest install script."
exit 0
fi