Update cloud-init scripts and documentation for enhanced DNS management and provisioning steps</message>

<message>Modify the first-boot.sh script to include an additional step for managing screen brightness during the provisioning process. Update user-data.bootstrap to improve DNS configuration by ensuring NetworkManager manages /etc/resolv.conf correctly, and remove obsolete scripts related to systemd-resolved. Enhance documentation to reflect these changes and clarify the setup process for users, improving overall network boot functionality and user experience.

emmc-provisioning/cloud-init/fileserver/screen-brightness.service

@@ -0,0 +1,22 @@
+[Unit]
+Description=reTerminal DM screen brightness daemon (ambient + buzzer)
+Documentation=https://wiki.seeedstudio.com/reterminal-dm/
+After=multi-user.target
+# Wait for the IIO light sensor and backlight sysfs nodes to be available
+After=systemd-udev-settle.service
+
+[Service]
+Type=simple
+# Ensure brightness starts in auto (ambient) mode on every boot
+ExecStartPre=/bin/sh -c 'mkdir -p /run/screen-brightness && echo auto > /run/screen-brightness/override'
+ExecStart=/usr/local/bin/screen-brightness.py
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=on-failure
+RestartSec=5
+# Needs root to write to /sys/class/backlight and /sys/class/leds
+User=root
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=multi-user.target