sched-host-tran: add base interfaces for Scheduled Host Transition

Implement interfaces to get/set scheduledTime and requestedTransition.

Tested:
1. Check scheduledTime
 # busctl get-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition ScheduledTime
   t 0
 # busctl set-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition ScheduledTime t 1
 # busctl get-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition ScheduledTime
   t 1
2. Check requestedTransition
 # busctl get-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition RequestedTransition
   s "xyz.openbmc_project.State.Host.Transition.On"
 # busctl set-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition RequestedTransition \
   s "xyz.openbmc_project.State.Host.Transition.Off"
 # busctl get-property xyz.openbmc_project.State.ScheduledHostTransition \
   /xyz/openbmc_project/state/host0 \
   xyz.openbmc_project.State.ScheduledHostTransition RequestedTransition
   s "xyz.openbmc_project.State.Host.Transition.Off"

Change-Id: Ie7da8034d37c1069db043772f35982ca821826ae
Signed-off-by: Carol Wang <wangkair@cn.ibm.com>
diff --git a/scheduled_host_transition_main.cpp b/scheduled_host_transition_main.cpp
new file mode 100644
index 0000000..40a3d4d
--- /dev/null
+++ b/scheduled_host_transition_main.cpp
@@ -0,0 +1,29 @@
+#include <cstdlib>
+#include <iostream>
+#include <exception>
+#include <sdbusplus/bus.hpp>
+#include "config.h"
+#include "scheduled_host_transition.hpp"
+
+int main()
+{
+    auto bus = sdbusplus::bus::new_default();
+
+    // For now, we only have one instance of the host
+    auto objPathInst = std::string{HOST_OBJPATH} + '0';
+
+    // Add sdbusplus ObjectManager.
+    sdbusplus::server::manager::manager objManager(bus, objPathInst.c_str());
+
+    phosphor::state::manager::ScheduledHostTransition manager(
+        bus, objPathInst.c_str());
+
+    bus.request_name(SCHEDULED_HOST_TRANSITION_BUSNAME);
+
+    while (true)
+    {
+        bus.process_discard();
+        bus.wait();
+    }
+    return 0;
+}