Dbus Based Gpio Event monitoring

This change provide the implementation for D-bus based Gpio Event monitoring.
For the platform not having direct GPIO access can use dbus based event
monitor by configuring dbus names in Json file. x86-power-control will monitor
the property change from the given DbusName and take appropriate action

Updated parsing logic of reading config values from json.

TESTED:Tested and verified in Tiogapass and YosemteV2. The existing functionality
is not broken after adding the JSON parser implementation in Tiogapass.

Signed-off-by: Priyatharshan P <priyatharshanp@hcl.com>
Change-Id: I480c62eccebf6d0a3c4609afaf24d55265d99602
diff --git a/power-control-x86/service_files/xyz.openbmc_project.Chassis.Control.Power@.service b/power-control-x86/service_files/xyz.openbmc_project.Chassis.Control.Power@.service
new file mode 100644
index 0000000..4d676c2
--- /dev/null
+++ b/power-control-x86/service_files/xyz.openbmc_project.Chassis.Control.Power@.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=Intel Power Control for the Host %i
+ConditionPathExists=/usr/share/x86-power-control/power-config-host%i.json
+
+[Service]
+Restart=always
+RestartSec=3
+ExecStart=/usr/bin/power-control %i
+Type=dbus
+BusName=xyz.openbmc_project.State.Host%i
+
+[Install]
+WantedBy=sysinit.target