Fix missing log directory after package updates

[kimasplund]

Resolves #3866 where NetBird service fails to start after package updates due to missing /var/log/netbird directory.

Changes:

• Add ensure_required_directories() function to post_install.sh that creates all required directories (/var/log, /var/run, /var/lib, /var/cache)
• Create systemd tmpfiles.d configuration for proper directory management
• Update goreleaser config to include tmpfiles in deb/rpm packages
• Ensure directories are created during both fresh installs and upgrades

This fix ensures NetBird can start successfully after package updates by guaranteeing all required directories exist with proper permissions.

Describe your changes

Issue ticket number and link

Stack

Checklist

• [x] Is it a bug fix
• [ ] Is a typo/documentation fix
• [ ] Is a feature enhancement
• [ ] It is a refactor
• [ ] Created tests that fail without the change (if possible)
• [ ] Extended the README / documentation, if necessary

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[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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