Add chassis intrusion sensor daemon

Chassis intrusion signal is read from PCH via I2C or from GPIO.
Create a new daemon to poll its status and expose to dbus.

Related patches to run test:
- meta-phosphor: dbus-sensors: Enable new service of intrusion sensor
https://gerrit.openbmc-project.xyz/#/c/openbmc/meta-phosphor/+/17063/
- redfish: chassis: add property of physical security
https://gerrit.openbmc-project.xyz/#/c/openbmc/bmcweb/+/17691/

Tested-by: Check intrusion status value by redfish,
verified PCH solution on WFP and GPIO solution on STP.

Change-Id: Id5e67abbd80bbf2ef502db49fa183d92d0d31bda
Signed-off-by: Qiang XU <qiang.xu@linux.intel.com>
diff --git a/service_files/xyz.openbmc_project.intrusionsensor.service b/service_files/xyz.openbmc_project.intrusionsensor.service
new file mode 100644
index 0000000..5b407e4
--- /dev/null
+++ b/service_files/xyz.openbmc_project.intrusionsensor.service
@@ -0,0 +1,12 @@
+[Unit]
+Description=Intrusion Sensor
+StopWhenUnneeded=false
+
+[Service]
+Restart=always
+RestartSec=5
+ExecStart=/usr/bin/env intrusionsensor
+SyslogIdentifier=intrusion-sensor
+
+[Install]
+WantedBy=multi-user.target