bug#63658: I add the file to /etc via a udev-rules-service in a guix system

[Julian Flake]

In case someone else needs to add these rules to /etc, here is how 
I did it:

I added the following udev-rules-service to my list of services in 
my operating-system definition

(udev-rules-service 'logitech-unify
(file->udev-rule
 "42-logitech-unify-permissions.rules"
 (file-append solaar 
 "/share/solaar/udev-rules.d/42-logitech-unify-permissions.rules")))

Best Regards,
Julian