feat(unattended-upgrades): add automatic security update configuration
Add Debian unattended-upgrades configuration files for automatic
security patch deployment:
- 50unattended-upgrades: Main configuration specifying allowed
origins (distro, security, ESM), package blacklist, cleanup
settings for unused kernels/dependencies, syslog logging, and
configurable reboot behavior
- auto-upgrades: Enablement settings for the automatic update
service
This ensures servers receive security patches promptly without
manual intervention, reducing the window of vulnerability.
Related: KNELServerBuild/ProjectCode/Modules/Security/secharden-auto-upgrade.sh
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