feat(ns-don): enhance session management with logging and expiration checks

[stephdl]

This PR adds time-based session management to the Don remote support tool:

• Tracks session expiration - Sessions now show how much time is left (default 24 hours)
• Auto-cleanup - Hourly cron job automatically stops expired sessions
• Extend command - New don extend adds 7 days (one-time only)
• Logging - All session events (start/stop/extend/expire) now log to syslog
• Bug fixes - Prevents double logging during cleanup and improves variable quoting

Result: Remote support sessions are now time-limited with automatic expiration, better visibility, and audit trails.

echo "[4/6] Simulating 25 hours have passed..."
current_time=$(date +%s)
old_time=$((current_time - 90000))  # 90000 seconds = 25 hours
echo $old_time > /var/run/don/session_start

echo "[7/8] Simulating 8 days have passed..."
current_time=$(date +%s)
old_time=$((current_time - 691200))  # 691200 seconds = 8 days
echo $old_time > /var/run/don/session_start

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[gsanchietti]

Remove also the init script

[Tbaile]

Good for me, will merge after image release

[gsanchietti]

@stephdl could you please update also the documentation inside nethsecurity-docs repo?

[gsanchietti]

I've found another problem: when don stopped or don expire is called, the script logs the same line 2 times:

Apr  7 20:14:50 NethSec don: Remote support session stopped
Apr  7 20:14:51 NethSec don: Remote support session stopped

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Pull request overview

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[Copilot]

I've found another problem: when don stopped or don expire is called, the script logs the same line 2 times:

Apr  7 20:14:50 NethSec don: Remote support session stopped

...

Fixed in 544bb69. The double logging was caused by the cleanup lock file living inside $base_dir — once rm -rf "$base_dir" ran, the lock was gone, so the VPN down callback's don stop could re-enter cleanup and log again. Replaced the lock mechanism with a simple check: if $credentials doesn't exist, cleanup returns early (session already stopped).

Remove also the init script

Removed in 544bb69. The [ -x /etc/init.d/cron ] && /etc/init.d/cron restart calls have been removed from both add_cron_expiration and remove_cron_expiration.