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.
Since diagonal key support was added in kernel 4.7 KEY_LEFT_UP
and KEY_RIGHT_UP are valid input symbols.
This means we can no longer use _UP as a suffix for transporting
release events from lircd to lircd-uinput, lircd-uinput now
interprets KEY_LEFT_UP/KEY_RIGHT_UP as a diagnoal key down event
instead of left/right key release.
