lirc: use upstream method to configure and run lirc

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.

packages/sysutils/lirc/scripts/lircd_uinput_helper

@@ -0,0 +1,24 @@
+#!/bin/sh
+################################################################################
+#      This file is part of LibreELEC - https://libreelec.tv
+#      Copyright (C) 2017 Matthias Reichl (hias@horus.com)
+#
+#  LibreELEC is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  LibreELEC is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with LibreELEC.  If not, see <http://www.gnu.org/licenses/>.
+################################################################################
+
+if [ -e "/storage/.config/lirc_options.conf" ] ; then
+	LIRCD_OPTIONS="-O /storage/.config/lirc_options.conf"
+fi
+
+exec /usr/sbin/lircd-uinput $LIRCD_OPTIONS "$@"