Allow udev rules & make it persistent (#210)

* Install default to lib

* Create hmip-rfusb.rules

* Create etc-udev-rules.d.mount

* Update hassos-config

* Update configuration.md

* Update rauc.sh

* Add ln

buildroot-external/rootfs-overlay/usr/lib/systemd/system/etc-udev-rules.d.mount

@@ -0,0 +1,14 @@
+[Unit]
+Description=Udev persistent rules.d
+Requires=mnt-overlay.mount
+After=mnt-overlay.mount
+Before=systemd-udevd.service hassos-config.service
+
+[Mount]
+What=/mnt/overlay/etc/udev/rules.d
+Where=/etc/udev/rules.d
+Type=None
+Options=bind
+
+[Install]
+WantedBy=hassos-bind.target