core: add function cleanup_lxc

[MickLesk]

✍️ Description

Introduces the cleanup_lxc function to perform system and package manager cache cleanup, remove temporary files, truncate logs, and clear caches for various language package managers. This helps ensure containers are left in a clean state after operations.

=> Tested with Ubuntu 22.04 / 24.04 / 24.10 / 25.04 | Debian 11 / 12 / 13 | Alpine 3.21 / 3.22

Next Time i will add this in all ct and install scripts as base function, so it cleanup after install and after update

🔗 Related PR / Issue

Link: #

✅ 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.