Add helper scripts for lircd and lircd-uinput so that we can
override lirc_options.conf and lircd.conf via files in
/storage/.config
Use separate systemd units for lircd and lircd-uinput, like in
upstream, and just add a ConditionPathExists to enable/disable
the services.
The lirc socket is managed by systemd via lircd.socket, like
in upstream.
Remove udev file for enabling lirc, this is now handled via
systemd only.