Add temperature-aware MD1200 fan control

das_fanctl.sh reads drive temps via smartctl (falling back to the EMM
backplane sensors), interpolates a fan percentage, and re-sends _shutup
on a 5s keepalive so the shelf does not revert to full speed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

log_rotate.txt

@@ -0,0 +1,8 @@
+Create a file in the /etc/logrotate.d/ folder with the following text
+
+/root/fan_speed/log/fan_speed.log{
+        rotate 30
+        hourly
+        missingok
+        notifempty
+}