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

Documentation/configuration.md

@@ -8,12 +8,14 @@ Format a USB stick with FAT32/EXT4/NTFS and name it `CONFIG`. Use the following
 ```text
 network/
 modules/
+udev/
 authorized_keys
 hassos-xy.raucb
 ```
 
 - The `network` folder can contain any kind of NetworkManager connection files. For more information see [Network][network.md]. 
 - The `modules` folder is for modules-load configuration files.
+- The `udev` folder is for udev rules files.
 - The `authorized_keys` file activates debug SSH access on port `22222`. See [Debugging Hassio][debug-hassio].
 - The `hassos-*.raucb` file is a firmware OTA update which will be installed. These can be found on on the [release][hassos-release] page. 
 
@@ -30,6 +32,10 @@ You can edit or create a `cmdline.txt` in your boot partition. That will be read
 
 The kernel module folder `/etc/modules-load.d` is persistent and you can add your configuration files there. See [Systemd modules load][systemd-modules].
 
+### Udev rules
+
+The udev rules folder `/etc/udev/rules.d` is persistent and you can add your configuration files there.
+
 ### Network
 
 You can manual add, edit or remove connections configurations from `/etc/NetworkManager/system-connections`.